The 1950-1990 period also corresponded with cheap oil (actually, that persisted through the late 1990s), abundant suburban real estate (prices started climbing earlier), freeway and highway construction (which congestion clawed back at beginning in the 1960s and progressively over the years).

The back-to-the-city movement actually had its roots in the yuppie trend of the 1980s, though it's been gathering steam with time. Downtowns in many major US cities (Chicago, New York, Los Angeles, as well as San Francisco) have have seen significant revivals over this period.