I'm not so sure I'd view the continuing trend of expanding suburbanization after the 70s oil shocks as the result of deliberate government policy.

I tend to think it was more the result of LACK of government policy coupled with a built-in presumption that suburbanization was the only logical way to absorb the expanding population. Prehaps it was just a matter of government neglect.

Also, don't forget that the in the 1970s most of the major US cities were still experiencing 'white flight' as the result of urban decay, rising crime, and and variety of intractable racial and social problems. For a lower- to middle-class family, living in a major urban area during the 1970s (with memories of the urban riots of the 1960s still fresh) was not the most pleasant experience.

Packing more people into already troubled and highly stressed urban areas simply made no sense, other than from a purely energy consumption standpoint. (I'm still not sure it makes much more sense even today.)

You are exactly right. It is all result of public policy neglect. To complete your point - the other fundamental reason you cite - rising crime and racial problems is also a logical result of government neglect and disinterest. US government has never had the goal of tackling these problems via social policies - its primary goal has always been creating a secure growth-oriented corporate environment. Corporate heads and multimilioneers don't really care about the beggars on the streets as long as their taxes are low.

The resulting fundamental problems in the society, suburban sprawl among them, are starting to show up now - when the growth phase is approaching to an end and the resources to keep poverty apart suddenly become scarce... it is of course an overused comparison but the same thing happened with the Roman Empire when it started running out of slaves. The barbarians came in.