That's true. But leftists are entrenched in Austin as well at the city level. I suppose, at the state level, once the state flips blue, the "default"/status-quo position will still be more low-tax/low-regulation, and that's an advantage for Texas (again speaking from a libertarian view point; I understand you won't agree if you share a different politics).

It still seems to me that Austin will converge to SF, given enough time, given that the people in both cities believe the same things, and in only a few years Texas will be blue.