I can tell you that lack of regulation also causes problems. My kids school is only a half mile away through medium density housing, and they still can’t make it the whole way without walking in the road because the city won’t force people to make sidewalks.
He's taking the piss. The hyperbole being "why won't the homeowners take it upon themselves to pull their children up by their bootstraps and build sidewalks to the school" in the sense that America is a hellscape car centrism and over self reliance.