Nashville’s Broadway. Photo: Daniel Slim/AFP/Getty Images

On a spring evening in Nashville, I join the line outside the Station Inn, the venerable joint where grizzled fiddlers and young banjo hotshots converge for the Sunday-night bluegrass jam. A decade ago, the squat stone structure was the only sign of life in an industrial tract down by the rail yards. The beer is still cheap and the music homespun, but outside the metal door is the Gulch, “a hotspot for young urbanites,” as the city’s visitor website puts it. There’s an Urban Outfitters across the street, next to a Lucchese store selling $500 cowboy boots. Around the corner, the Turnip Truck supermarket is running a sale on kombucha. Down the block, a cluster of high-rise rental buildings sprouts from the vale of parking lots and one-story warehouses. This is what the 21st-century American city is supposed to be, a satisfying and active mix of cultural holdovers, storefronts, and apartment buildings. Except the sidewalks are empty and the streets as wide as rivers. In reality, it’s a lukewarm spot at best.

America is getting cities wrong again. For decades, planners, mayors, and activists have promoted the dense, walkable downtown as the solution to a vast array of problems. Studies and news articles have celebrated the young people who flock to urban centers, live in apartments, walk to school, and bike to work, promoting diversity and tolerance, raising property values and coffee standards, and foretelling an end to sprawl. That optimism has curdled, largely because of the side effects of success. Richard Florida, who once believed the “creative class” would bring a new inner-city Eden, now thinks that saving downtowns is a good way to destroy them.

The hope that American cities would gradually morph into miniature Manhattans or heartland Copenhagens evaporates as soon as you try walking around Nashville or Phoenix or Louisville. In most of those places, it’s not clear what the word “city” even means: neighborhoods of single-family houses don’t look much different on one side of the county line than they do on the other. Often, a theoretically walkable neighborhood is actually a tourist strip, or a tiny nugget that you can cross in just a few minutes on foot, before you hit a multi-lane road or a strip mall. A shopping district consists of a coffee place, a restaurant, and a boutique or two.

Nashville is a boomtown, slurping up millennials and immigrants to work in health care, tech, auto parts, and education. A high-powered global music industry coexists — and overlaps — with a network of amateur virtuosos and barely-paid pros, who keep the bars on Broadway afloat and the tourists entertained. A free shuttle bus plies a tourist loop, but the most visible form of transit is the pedal tavern, which gradually slows over the course of the evening as the passenger-bikers get more sloshed.

The signs of ferment are familiar. Cranes bob and nod on the skyline; developers lure newcomers with glass towers, insipid apartment complexes, and the delights of future density. Brunch, an elevator ride away! Bars you can stumble home from without getting behind the wheel! Every day delivers nearly 100 new residents, many bringing fancy educations and 401(k)s. The newest employment juggernaut is the investment management firm AllianceBernstein, which recently announced it would move its headquarters from New York, bearing more than 1,000 new jobs and six-figure salaries.

Yet many longtime Nashvillians watch the celebrations from the sidelines, which keep getting moved farther back. “The influx of jobs means an influx of people with high incomes, coming to a state that’s relatively cheap,” says The Tennesseean’s editorial writer David Plazas, who spent a year documenting the disorienting and sometimes traumatic effects of the boom. “We have to ask ourselves a question,” says Paulette Coleman, an affordable housing advocate: “In our efforts to grow and improve, do we address the people of Nashville of all economic levels?” So far, the answer is no. The city is constantly playing catch-up, waiting until affordable housing shortages, inadequate transit, and financial inequities reach crisis levels before addressing them with half-baked measures. The emergence of affluent sort-of walkable areas is pushing African-Americans and immigrants into far-flung areas like Goodlettsville, lengthening their commutes and creating more congestion on the roads. Density is making the city more, not less, car-dependent.

Advocates consider the benefits of walkable cities self-evident, but a lot of other Americans reject them with disgust. In California, an alliance of voters on the left and right recently quashed a ballot measure that would have allowed for more apartment buildings. A similar coalition of odd bedfellows rejected Nashville’s $5.4 billion proposal for a light rail network that would take decades to build and skip some of the neighborhoods that might need it most. (They also disdain a cheaper, quicker, and more flexible solution: buses.) A few days after the transit vote, Plazas livetweeted a discussion at Progressive Baptist Church, where a preacher compared the transit plan and other big-money development projects to the promise of “40 acres and a mule,” which is to say a racist scam.

Sixty years ago, downtown Nashville was a mixed and bustling place, where African-Americans wielded their postwar economic muscle by patronizing — and, in 1960, boycotting — shops that refused to serve them coffee. Whites made their exodus along federally funded highways to suburbs where they obtained federally insured mortgages and reaped the tax benefits of homeownership, privileges mostly denied to blacks. Even the Grand Ole Opry abandoned its storied Ryman Auditorium for a shopping center/hotel complex ten miles away. Today, that’s where Nashville’s most convincing pedestrian experience can be found, amid the ersatz woods and indoor gardens of the Gaylords Opryland Resort.

In 2002, a citywide plan allowed residential construction downtown, inaugurating a demographic reshuffling. Today’s revitalization policies are organized around corporations, sports, and country music, a stylistically diverse but overwhelmingly white genre. J.T. Gray, who runs the Station Inn, is a guardian of Nashville’s old-time soul, which the newcomers simultaneously cherish and threaten. “We’re going to keep on doing what we’re doing, exactly the same as we always have been,” he says. But Gray’s precious relic exists at the pleasure of its landlord, a family-owned plumbing company, and the heavyweights’ goodwill. “The developers are fans, and if we’ve got them behind us, we’ve got the city behind us.”

After the show at the Station Inn, I walk the mile or so into the heart of downtown, onto the Broadway viaduct that vaults over the tracks; past the medieval stone bulk of Union Station (now a hotel), looming like a haunted castle over the desolation; past the parking-lot graveyards of buildings demolished decades ago to make room for skyscrapers that haven’t yet shown up. I pass only a handful of other pedestrians. A 20-minute stroll feels like an hour-long slog. Walking always lifts my spirits; here, it snuffs out the music’s afterglow and makes me crave a drink.

My itinerary takes me past the site of the future Nashville Yards, a billion-dollar 15-acre megaproject so closely patterned on New York’s Hudson Yards that it will even have its own High Line. Its architect, Joe Bucher, a partner at the firm Gresham Smith, says that the buildings will be threaded through with shopping walkways, piazzas, and a 1.5-acre park — semi-public spaces that will help graft a new neighborhood onto a dead street. A large music venue will “make the development hum and sing.” For now, Bucher acknowledges, even apartment dwellers need cars, but he is bullish on self-driving automobiles, and he has designed the garage so that, one day, parking spaces can be recycled into offices or stores. That long-term future may be bliss, but in the short- and medium term, density is just going to supercharge the traffic.

The market is propitious, yet a metropolis’s crackle comes from the variety of its people and the intertwining of disparate lives. Growth and density are powerful tools, but only when harnessed to a humane vision of mixture and complexity, when old buildings and rooted populations endure alongside the new, when architecture is calculated to delight and last, and transit is stitched into an urban fabric that expands organically, not in isolated lumps.

Even after Nashville Yards opens, the rest of downtown will still look like an orthodontist’s nightmare: more gap than shine. But to Bucher, that’s progress, one step in a coordinated, nationwide, multi-decade campaign. “As we wipe out postwar development, a lot of southern cities are becoming vertical and dense. New York is on its sixth or seventh generation of buildings. In Nashville, we’re just getting to generation two. Here, a big project doesn’t get dropped into an already vibrant neighborhood; it creates the city around it,” he says.

That crop of generative construction includes mammoth sports and entertainment complexes — Bridgestone Arena, Nissan Stadium, a convention center, the Country Music Hall of Fame — that draw in crowds at certain hours, then spit them out again to disperse just as quickly. Neighborhoods don’t flourish in the shadow of these regularly scheduled megaliths. Bucher insists that a residential building can seed a city more efficiently: just look at 505, a 45-story residential skyscraper on the corner of Fifth Avenue and Church Street. “If you stand out in front of it long enough, you see an amazing cross section of people. They make a lot of money or have a lot of wealth: that’s the only thing they have in common.”

That monoculture of shallow-rooted affluence springs from the financial wildfire that burned through 2008, says Jonathan Miller, a New York–based real-estate consultant. With interest rates low and bank loans scarce, Wall Street has swooped into the real estate market, looking for promising places to park excess cash. Investors hunt for the high returns that only high-rise luxury housing can bring, since tall buildings multiply the value of land. Faraway private equity firms have hijacked urbanists’ agenda, bringing forth a kind of metropolitan version of Westworld: a place that looks like a city but isn’t.

The Vancouver-based urbanist Brent Toderian came away from a visit to Nashville impressed with handsome and inviting examples of gentle density: low-rise apartment buildings and the townhouses that some locals scornfully refer to as tall-and-skinnies. But “these small moments of improvement in a sea of business as usual” don’t begin to deal with the insidious addiction to cars, wide roads, and free parking. It’s not enough to build big: if Nashville really wants to live up to its aspirations, it will have to concentrate growth, rather than scatter it nodes. The downtown population, which is growing at a brisk clip, currently stands at about 13,000. That’s not nearly enough, Toderian says, to create a pedestrian culture like that in his hometown of Vancouver. “A fundamental game changer would be adding 60,000 people downtown, 7,000 of them children.”

And yet it’s not clear how long the new Nashvillians will want to live in the towering paradises that were built for their benefit. New neighborhoods like the Gulch and Germantown depend on an endless supply of glamorous, leisure-seeking young globalists who transition seamlessly from architects’ renderings to real life. Urbanists have been counting on that cohort to internalize the virtues of density. Having started out clustering, walking, biking, and ordering in, surely they would continue to do so for the rest of their lives. It turns out that millennials, too, migrate to the suburbs as soon as they have kids, driving up the cost of single-family houses within commuting distance of core markets. All of which suggests that all the apartment complexes going up in central cities are really temporary housing for a mobile population. “The new urbanism story was about millennials, millennials, millennials,” Jonathan Miller says. “It didn’t include growing up.”

Nashville may eventually generate the kind of dense collaborative ecosystem that makes a prosperous city feel alive at sidewalk level. But it’s not looking good. The mayor’s office recently floated a proposal to hand over a small park across the street from the public library, plus $25 million, to the developer Tony Giarratana, who would fill the lot with yet another high-rise condo and build living quarters for 100 homeless people on another site half a mile away, right next to a major highway. That outrageous boondoggle would mean sorting the privileged from the powerless and making sure they never meet. That’s no way to make a mixed and vibrant city: it’s how you plant the next generation of ghettos.