I don't think it's about the type of tech. Calling both groups "tech companies" is misleading to start with. The California start-up ecosystem is based on applying tech to create consumer products and once market fit and growth potential are evidenced it's straightforward to scale it globally.

Biotech companies are developing new technology, in a highly regulated environment where, like other comments point out, there's a predictable economic niche. They only share a denomination, the dynamics are wholly different.