Even finance experts like Matt Levine use index funds. Unless you are mega rich and have connections, you almost certainly have no advantage against the many people who work 100 hours a week trying (and often failing) to beat the market.
Just VTSAX and chill.
That and the goal of many (most?) professional investors is not to beat the market. For some they just need to have higher returns than cost of funding and anything positive is accretive. Others sell fund investors on things like low market correlation. Or others have more specific goals like hedging future fuel prices for an airline.
Point being, individual investors have completely different goals from most professional investors and as you point out, "VTSAX and chill" is the way.
That's the issue: successful firms which beat the market don't keep doing it on behalf of other people for very long.
Answer: because they make more money from the fees than they do by "beating the market"
The truth is if you beat the market by pure luck once you can market your shit fund and lure in thousands more investors for decades.