> barring terrible luck, nearly anybody can be successful if they’re willing to make the sacrifices, work hard, learn quickly, and keep at it long enough

The problem is, I don't think we have nearly enough global signal to make that assertion. Wouldn't we need some objective metrics on how many people succeed vs. fail correlated against their level of effort?

I have some pretty deep-seated concerns that we have assumed "fortune favors the brave" without comparing that assertion objectively to other hypotheses such as "fortune favors the sons and daughters of the successful" or "fortune favors the pretty" (where "pretty" here is standing in for whatever mostly-permanent physical characteristic one might choose: sex, gender, skin color, working legs, what have you). To be certain, from a personal standpoint the only one of those you can control directly is your own boldness so that matters in terms of personal choice... But policy has to look at the level of not personal choice, but the effects rules, laws, and incentives have on sculpting society as a whole.