And what about the free-wheeling, non-traditional culture (embodied in the Homebrew Computing Club)?
These two factors created Silicon Valley. Federal money subsidized the semiconductor boom, which brought a lot of technical expertise to the area. Then the open-minded culture created the perfect environment for entrepreneurship.
It seems like the formula for success is: (1) Massive exogenous funding (on scale only the federal government can do) + (2) A highly open-minded culture that accepts failure as an inevitable part of creation.
Honestly, there's just not a lot of places that qualify. Pretty much all of the east coast, mid-west, and south are too conservative. And nowhere is really receiving massive loads of external funding like the Bay Area did in the 20th century.