So was Mark Zuckerberg. If you don't come from a well-to-do family its hard to turn down a million dollars for a side project.

Look at the founders of Google, who came from middle class families, and would have been more than happy to sell Google in the early days for even 1 million dollars.

I'm very curious if Gates'/Ellison's/Allen's sons (or any of this guys that made fortune with computer programming/software) know about computer programming. Sometime ago I've read (a sorry, but I don't remember where) that Gates' sons could to use the computer about two hour per day only.