It seems very unlikely that Renaissance/Medallion constantly finds these things, whereas other operations almost never do.
The conspiracy theorist in the back of my brain thinks that Renaissance/Medallion hires a lot of eggheads so they can plausibly claim to keep finding mathematical and operational edges, but the actual money-making strategy might be something else entirely.
Not true at all as far as I know.
Name one member of RenTech that went else where and made similar returns; I don't think you can because its never happened as far as I know.
The closest I can think of is Pavel Volfbeyn and Alexander Belopolsky leaving to join the Millenium fund.
Their performance there was so poor even not comparing their performance to what RenTech did so much so that they were let go even after Millenium settled the lawsuit with RenTech that allowed them to stay at Millenium.
Renaissance focused on finding and developing novel mathematics that can be exploited to find an edge, some of which is extremely esoteric and unique, and then massively automating that. Consequently, they can find more new edges before breakfast than some hedge funds find all year. The real effect is that they don't need to milk a dying edge for returns because they are constantly generating new ones, and they can pick the best of the bunch at any point in time. The investment side of the business is mechanical. Their recruiting has reflected their deep interest in novel theoretical approaches to edge discovery.
In a sense, they are a higher order abstraction of a more typical hedge fund.