The startup ecosystem does seem biased towards younger folk, but I dunno if I'd say it "penalizes" older founders. I think people make choices throughout their career, and those choices will change the payoffs for future choices. As you get older, your choices have less potential impact, because there's less time left in your future.

This only applies if you have optimized your career around being an employee, though. Someone who makes $300K/year obviously has, and has picked up quite a few skills on being productive and navigating office politics. But a 50-year-old homeless bum who just got his life back together faces the same incentives as the 22-year-old startup founder - perhaps even moreso, because employers will look at a gap in work experience with suspicion.

And it seems like many of the businesses started by older founders fit this pattern - either they've just been fired and lost everything, or they're housewives returning to the workforce, or they're senior citizens looking for a career change. Once you've got nothing to lose, you've got everything to gain.