The true star traders would leave after a couple of years to start their own hedge fund;
instead of making someone else rich,

...and you would be left with just another ho-hum failed/average fund,
Steve Cohen and Soros and Paul Tudor Jones and others all followed the same path.
And besides, and slightly more importantly, it kind of becomes impossible to trade once you're a huge hedge fund.
The retail trader generating huge returns has a competitive advantage; compare a 100K trading account...with a 100 million account, or a 100 billion account,
It's just like the animal kingdom...the smaller animals are much more agile and nimble for high velocity moves/returns -- a blue whale...is a slow dinosaur, that creates a small tidal wave just releasing a fart,