So the theory would be that since the middle class were busy rehabilitating cities rather than building out on the fringe the typical relationship between miles and GDP was broken.  Interesting.
I worked on a fair amount of gentrification in the late 70s/early 80s in Takoma Park, Woodley/Zoo, and other areas of Northwest DC.  So many places were going condo that the renters weren't too thrilled to see us show up with measuring tapes.  There was a lot of infill, too, like Foxhall Crescents on the old Rockefeller land.

Of course, we were building new towns and suburbs like gangbusters, too.