One thing that made YC great was that it was started to allow the original 4 partners to learn how to be investors. The first batch wasn't intended to be profitable, it was intended to reveal what works and what doesn't. (Luckily for YC it got a lot right by accident). Sure YC could go back to small batches and small investments but they can't go back to "let's figure things out with only rough theory as a guide" because YC is no longer the startup born out of ignorance and curiosity it once was. You can't forget lessons learned and dial back your sophistication. The magic of early YC isn't lost forever but it will be refound among the next group of rich people who are willing to spend a bit to figure out if this investing thing is to their taste.