I’ll note my experience with the Austrian town near which my mom grew up. Where once it was a relatively self-contained market town serving local farmers, it’s now a suburb of the booming metropolis of Salzburg. There’s still town-like density and open land between Seekirchen and Salzburg, but the yuppies are coming--indeed, they have come--and are bringing their chain stores with them. We discussed it all here. For me the bottom line is this: the environs of Salzburg are a little more American-looking than they were when last I visited.
These things are, of course, matters of degree: houses and cars are bigger in the U.S. than elsewhere. I see some evidence that the latter are getting smaller, but little that the former are. Infill housing everywhere I see it consists of big houses (perhaps energy-efficient and "green," but nonetheless BIG) on little lots. And as Eduardo Penalver, the WaPo author, points out, we haven’t yet really begun to talk about "affordable" middle class housing as infill. Certainly the market won’t produce it, as the margins aren’t there for developers (unless we’re going to become again a nation of tenement dwellers). What’s more, unless we’re going to become a nation of home-schooling tenement dwellers, much will have to change before people other than the wealthy or childless will move close in.
In the end, then, my question mark is probably much bigger than is Penalver’s or Deneen’s.