This month, employees at Apple began moving into the company's gargantuan new headquarters in Cupertino, Calif. Nicknamed the "spaceship," the ring-shaped building cost an estimated $5 billion, the most expensive office building in history. And with 2.8 million square feet of office space and 11,000 parking spaces, it's one of the biggest.

But to many people, the Apple spaceship -- like similar Silicon Valley headquarters for Facebook and Google -- typifies the biggest challenges of the new tech economy in the San Francisco Bay Area: Massive, isolated corporate campuses plopped down in the 'burbs, which drive up housing costs and force many workers to endure hours-long commutes.

The real problem, according to many experts, stems from suburban housing policies that prevent dense development near job centers. And it's certainly true that housing and zoning laws in Silicon Valley suburbs have made it difficult for all but the richest tech workers to live near their jobs.

But a new report from SPUR, a civic planning organization in the area, makes the case that many of the region’s woes could be addressed simply by encouraging major employers to set up their corporate campuses near transit stops.

At first blush, such a call might seem unnecessary. As Governing reported last year, many companies are already gravitating toward downtowns. Tech firms like Red Hat in Raleigh, N.C., and even behemoth corporations like General Electric, which last year moved its headquarters from suburban Connecticut to downtown Boston, are locating to city centers to attract talented young workers who like working and living in walkable neighborhoods. In the Bay Area, some high-profile companies have even established their headquarters in the core of cities, including Twitter and Salesforce in San Francisco and Uber in Oakland.

SPUR points out, though, that those high-profile relocations make it easy to overlook the dominant trend, which is that most new office space in the Bay Area is being built more than a half-mile from a regional rail station. Only 28 percent of Bay Area offices that opened between 2011 and 2015 were close to rail stations. (By comparison, 93 percent of all office space being developed in the Washington metro area is within a half-mile of a Metro station.)

That's a throwback to 1950s-style office parks, the report says. “This environment emerged in an era of wide-open spaces, cheap land and easy mobility by car -- an era that is long past. Today that same environment, built for near-term expedience, is expensive, congested and ubiquitous. Nightmarish commutes and soaring home prices are taking a toll on the Bay Area’s prized quality of life, challenging its long-term competitiveness,” the SPUR researchers write.

“We have reached the limits of our 20th-century landscape, and our physical environment -- so disposable and yet so persistent -- is holding us back,” they add.

SPUR offered four main reasons why tech companies have been reluctant to give up their office parks and suburban campuses for transit-friendly locations:

Large, open spaces: Because of their organizational structure and culture, tech companies tend to want big, flexible spaces that make it easy to assemble teams for ever-changing projects. Putting workers on separate floors can prevent them from collaborating with each other. That’s why Facebook recently built a 430,000-square-foot workspace. It’s also why tech companies that do locate in more urban areas, like Uber and Twitter, often pick old industrial buildings that also allow for open floorplans.

Security and intellectual property: Tech companies like to keep a tight lid on their trade secrets. One way to prevent intellectual property from falling into the wrong hands is to keep all your employees cloistered away from outsiders.

Business-cycle considerations:The boom-and-bust nature of Silicon Valley means that companies need to be prepared to grow rapidly if their projects take off -- or shut down quickly if they fail. That makes modular buildings in office parks, each with its own parking lot, an attractive option. But that comes with a cost, the authors write:

“These employment centers not only lock in auto commuting, but they can never coalesce into the kind of contiguous, walkable environments that make other travel modes possible. The expectation of rapidly repurposing buildings in the marketplace makes any deviation from the norm -- and hence any innovation in the Silicon Valley landscape -- very much the exception.”

Employee preferences: Companies are always competing to get the best talent. In the past that meant offering workers all sorts of on-site services like cafes and gyms, as well as, in many cases, private shuttles to get to work. In 2014, Silicon Valley companies accomodated nearly 37,000 boardings on 765 buses on an average day. But the preferences of workers are changing, especially among younger employees. They’re increasingly looking for walkable, urban environments, which explains why some tech companies are settling in downtown San Francisco or Oakland instead of the suburbs outside of San Jose.

The SPUR report offers a number of recommendations to help change the urban design of the Bay Area.

It advocates for cities to change their zoning codes to allow more growth near transit stops and encourage mixed-use development in those areas. Bus rapid transit and rail service should be expanded to connect more neighborhoods. Local officials should create managed toll lanes on highways to help alleviate congestion. When it comes to the buildings themselves, SPUR says company facilities ought to be accessible by foot and close to the street.