Didn't he have his (rather rich) family as a safety net? That's got to cause wonders for your mental health and emotional stability, even at 0 income.

I think that’s true but the “rich” part is not really relevant. Personally I can sort of relate to his life journey, and I come from a very much not rich immigrant family. I just remember not understanding why people cared about money instead of say learning more math. But looking back there was always an implicit understanding that no matter how bad things got I could crash on the couch and get a meal at my parents place or something, so hardship never really crossed my mind.

Ok, then treat it as "always having a plan B".

Sure, but is that super uncommon? I’m judging by the number of people I went to high school with who now live with their parents. They could all treat it as a fallback and otherwise follow in pg’s footsteps, but none of them do.