For Renaissance specifically, their signature fund has been closed to outside investors (with all funds returned) for decades, so pension funds aren't able to take advantage of their outperformance. I believe their publicly-available funds don't have nearly the same kind of returns.

With all that aside, better liquidity and pricing of risk is the overall systemic value that all speculators in the market provide. You be the judge as to whether the remuneration is commensurate with that value.