That's the crux of the problem in the US. Vast swaths of land are dedicated to single-family homes (and ONLY single-family homes). You literally couldn't build a small grocery next to these homes if you wanted. And the hurdles to getting a zoning change as so high that developers just build strip malls on the outskirts of town/subdivision.

We're beginning to see some progress in the DC suburbs, with more mixed-use "village centers" being built in the 'burbs. My main complaint with these is the development is done in one pass by a giant corporate developer, leaving the area feeling very sterile (compared to an old urban downtown in a small city, which might not be as clean, but has a more organic mix of businesses). IMO, of course.