Zuckerberg owns Facebook though. It’s a lot easier to make bold decisions when you’re the majority shareholder.

Edit: though emphasis should be put on “easIER” because it’s still far from easy.

This. Without knowing the guy, he seems to be a) very comfortable taking a lot of risk and b) it's actually not that risky for him to blow $20 billion.

There aren't many cases like this. Larry/Sergey were more than comfortable risking $10 billion here and there.