We are already seeing that Uber/Lyft are causing declines in the usage of public transit, and there could actually be decreasing appetite for public transit investment. Compared to the rest of the US, the Bay Area is actually already pretty good when it comes to fraction of workers commuting by transit (#2 or #3 after New York City and possibly Washington, D.C.). Unfortunately, I find that most people are all in favor of other people using public transportation so that they can drive where they want to go faster. Transit only gains massive adoption for particular commutes where it is substantially faster than driving.