most companies are started by accidental entrepreneurs. steve jobs was a hippie basically, larry+sergey were doing phd work, zuck wanted to get laid at harvard instead of studying for finals, etc.
In fact, it seems to me most of the succesful folks are motivated by the fact they are going to do something cool and have fun and not necessarily by the idea of making billions. That is the one thing I cannot stand about mixergy: it's always about millions, billions and gazillons.