While I agree that outperformance is likely random, this is one of the most common yet least persuasive arguments.
How would said person know they had such talent and keep it to themselves? IRL, they would get their Ivy MBA and start with VG/Fido/Black Rock or a hedge fund as a junior for a decade. Then if they were really good they would get to manage a large mutual fund. It would take another 10 years for them to "prove" outperformance. Then at 45ish they get to decide do I play with OPM and make $XM/year salary/bonus or strike out on my own with whatever capital I have accumulated. Some would do the latter, but many would "diversify" by taking the megacorp OPM income and investing their own capital in parallel. Honestly, outperforming the market by one or two percent (which is what we are talking about when we say "beat peers") isn't some secret sauce that will make an individual wealthy in just a few years.
The ones that make bank in hedge funds in their 20s/30s are "aggros" as we say in poker. But that is a high variance game and it is not obvious it is best for any individual player due to the variance. Likely that more bust out than win.
Agree completely. The "why would they not invest on their own and buy an island/" is silly for many reasons.