Because he managed to combine the job, open source work, and to a large extent I expect, social life, into the same thing. That's the chicken and egg problem; you can do it once you 'make it', but getting there is tough without significant sacrifice.

He has a fulltime job? AFAIK, he's independently wealthy these days.

He deserves to be (at least as much as Jobs or Gates). A lot of the internet uses his software