But yes, its an absurd measurement. Whether a dude was worth $700M or $1.3B at age 29 or age 33 is beside the point.
That the worlds economic system rewards winning competitive endeavors is completely "natural". The reward being determined by actual consumers of those products, even if you yourself are not one directly.
Out there is a person or a firm that's really wealthy from being the best at mining and refining silicone. And another one that's good for turning it into wafers. And another one that's good at designing chips and circuitry and boards. And another that's good at writing low level software, and high level software. And another one at making radio antennas, and LCD displays, and ad infinitum. And they're all fucking rich and have yachts and college protestors all over will decry them as ruthless capitalists and shit.
And the cumulative result of all of that is now there exists a handheld device that Americans use for 4-5 hours a day, everyday, for 4-5 years, and it'll have cost them a total of 20 hours of average gross wage. That's fucking amazing.
People being allowed - encouraged, even - to pursue wealth by creating things that other people value is a good thing. What does it matter if they were seeded with outside money or parental money. And anyway if you have a problem with that, you have a problem specifically with inheritance tax, not with "the system". It's pretty cool that normal people have the option to get basically whatever food they want, whereas in the past they were limited to 2 pizzerias and 3 chinese shops in their city. I don't use Doordash, I don't contribute to their revenue, I don't buy their stock . But the mere fact that they're rich doesn't make you or me poor. A lot of this grumble is really just driven by ego.