Not just from a billionaire's trash. Not many people can afford to buy real estate in the Bay Area, but there are many people with excess cash who can buy a lot of goods. And so many people (read tech workers) who are not from the Bay Area--or even if you are--change residences quite often. What this means is that they often discard perfectly good items in the trash.

My wife and I, when we lived in Sunnyvale, would find perfectly good items (a TV stand, chairs, tables) in the trash in our apartment complex from people who, I'm assuming, moved.