Actually having a giant amount of money to throw at a hedge fund is counterproductive. In order to invest all that money, a greater number of investments will need to be made. And the more investments one makes, the more likely it is for them to revert to the mean, performance-wise.

It's a simplification, but if a hedge fund manager finds a fantastic investment for $100mn, but they have $100bn to invest, they have to be able to repeat that feat over and over and over and over.