If I had a dollar for the number of times I've been told that the problem with American suburbia is a "lack of planning" or "uncontrolled growth," I could treat myself to a stay at a nice beachfront resort. The truth is, we have plenty of planning in brand-new suburbs. We are, if anything, overdosing on planning. We are fully in control of growth. Our cup runneth over with bureaucratic process.

What we lack isn't planning. It's basic financial solvency.

I'm going to take you on a tour of the front lines of suburbia's march into the countryside in Lakewood Ranch, Florida: a behemoth master-planned community that was cattle pasture 20 years ago (hence the "Ranch" part) and is furiously expanding. Let's look at it through the lens of one concept that illustrates just how dysfunctional the new places we're building are: the ratio of public infrastructure to private wealth.

The Public-Private Investment Ratio is Out of Whack

A good benchmark for the financial viability of a place is the ratio of public to private investment. The physical public realm—our streets and sidewalks; our water and sewer pipes, pumps, and hydrants; our streetlamps; our power lines; our landscaping berms and drainage canals—all of it is a platform for building private wealth. It exists to facilitate human activity: our homes and businesses and anywhere else we forge community, transact with each other and create value.

Some portion of that value, in the form of the measurable financial wealth created in a place, is taxed and provides the revenue stream that local governments need to maintain the public realm over the long run.

It is self-evident that if the public-private ratio is too high, a place won't be viable to maintain. Imagine a 1:1 ratio—sure, you can buy a $300,000 house here, but the infrastructure supporting it is going to cost you another $300,000. No one would take that deal. We've suggested before that a public:private investment ratio of more like 1:20 or 1:40 is a hallmark of a financially viable place: one where people will gladly hang around, pay their property taxes and feel they're getting a good deal.

What do you think the public : private investment ratio looks like in the newest parts of Lakewood Ranch? Check out all the things you see here that cost money to build and maintain, while producing no private, taxable wealth in and of themselves: