> There are more than 2,000 billionaires worldwide but only about 480 NBA players (32 teams with roughly 15 people on the roster). And if you think about it, becoming a billionaire usually involves multiple skills (good at programming + business, bill gates. Good at research/analysis + cultivating a rare temperament that allows you to act on the insights produced by the research even when everyone around you is losing their shirt, Warren Buffett etc, etc).

That's not really true. Once you are billionaire you can stay a billionaire for decades. Meanwhile most NBA players don't have long careers, many stay in the league only for a few years. I'd expect that over 10-20 years there have been more NBA players than billionaires.