AT&T pulled fiber in San Jose and Sunnyvale about a month ago. Supposed to be lit up around the end of the year. Other cities are possible as well, those are just the two where I've actually seen the fiber.
Because rolling out a fibre network is very very very expensive. People who think they are entitled to certain speeds, data caps, or prices, don't understand this. That's why Google Fiber is reconsidering their investment. It simply is too expensive.
If you have a problem, you can ask your government to force Comcast to rent the network, as it happens in civilised countries like mine, but that makes it harder to compete in price.
How is it possible this is the only thing available in Silicon Valley?