I went long stretches where I only used my car when I wanted to go to a different city or wanted to carry more cargo than would fit in my panniers.
Unless things have changed a lot (it has been quite a while) I'd expect Cupertino to be fine for the kind of people who are actually in shape for biking.
For that, though, we lack virtually any sort of night life, and have very few non-chain restaurants/stores/etc. It's a great place to raise a family, but horrible to attract the "20-something Ruby Rockstar" developer, despite the 4-year university down the road.
This is just false; San Francisco is plenty walkable and public transit generally works quite well, despite the grousing you may hear from the people whom it has spoiled.
I live in SF without a car and I'd be hard pressed to name three friends who do have a car.