It would be interesting to see how the different languages stack up in getting jobs in the bay area. The bottom line is that web application developers in general are getting lots of job offers there (assuming that Ruby developers aren't having a problem.) I couldn't see a situation where all the Ruby developers there are getting snapped up and a glut of PHP developers are being left out in the cold. In the world of freelancing, I'm certainly not seeing a lack of work for PHP developers, though you have to cut through a lot of noise to find the decent jobs (still not lacking though)
I would think that your general skills as a developer would be important. Versatility and productivity with your tools is probably important. If you have that down, then I imagine you could easily pickup the same with a different language.
Edit: I also wonder if it's any good to have a job in the bay area making $90K+. That's an expensive area to live in, I think I would be just as happy freelancing for half that (or just as much) from a cheaper area. However, it also seems to be the mecca for developers, so maybe that's all you need as an excuse. ;)