One path to better jobs: More density?

That's a solution proposed in the NYT - but as Paul Kedrosky quotes, the authors have a strong sense of the limitations - and population density isn't what comes first in "job creation" (NYT via Paul Kedrosky):

DENSITY isn’t a magic elixir. One can’t create wealth just by crowding people together; otherwise the super-dense metropolitan areas in emerging Asian countries would be richer than American cities. Density simply facilitates interaction. Interactions translate into wealth when a population is educated and local institutions support private enterprise and entrepreneurship.

That said, I'm not sure that density isn't an effect of "a population educated [to] and local institutions [that]  support private enterprise and entrepreneurship."