Perhaps people who are financially set want to just try out new things. The author here rips on the facebook CTO, because whatever else he is doing will not be as successful? If he's the CTO of facebook, I'm sure money almost doesn't even enter the picture here, he's set for life, and wants to see if he can create his own baby. No problem with that.
Yeah, I noticed that: Sometimes success is not the only aim for starting a startup. There is also the sheer joy of working on something that you conceptualized and thought about. Irrespective of whether it succeeds or not, that feeling is probably one of the factors that motivate people to leave high paying jobs to do stuff like this.
