Ahh, sorry. I think I mis-read your comment. I thought you were questioning the existence of free-wheeling culture in CA.
As to why CA, I don't think there is any one reason. The weather and geography are huge. It was a lightly populated state in the 1950s, so real estate was much cheaper than on the heavily populated east coast (big for both start ups and 'artistic' types). And the gold rush mentality is/was pervasive, which I personally think leads to a government and culture that is generally supportive of start ups and small businesses. While CA has a reputation for being unfriendly to businesses, the taxes and regulations are largely targeting big businesses. So that leaves more room for small start ups to compete.
Only seemingly non-random factor you gave is the Emerald Triangle, which could be the answer.