The Medallion fund is a whole other kettle of fish. Medallion uses extremely sophisticated models which took Jim Simons and his team of math wizards more than a decade to figure out, using vast amounts of historical data and computation. The fact that nobody else is replicating their performance should tell you just how difficult it is.
In 2019, 71% of actively managed funds lagged behind their benchmark according to the S&P. In 2020, it was "just" 57% [2]. Meanwhile, 70% of active funds have been liquidated the last 20 years. There are of course years where actively managed funds are the winners, but over time, actively managed funds tend toward the mean, either lagging or matching the S&P 500.
[1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3197185
[2] https://www.spglobal.com/spdji/en/documents/spiva/spiva-us-y...