Just because only 1 in 500 makes it to a billion, does not mean the other 499 are failures. Plenty of startup founders turn a few million into much more.

If someone has an idea that 'only' makes them 20 million, I would call that a great success; even if it takes dozens of years to get there.

yes but again, who has $2M to bet, even at 1/500 odds? You have to be a billionaire to make 500 bets hoping one hits, then you’re back to just being a billionaire again.