I think the real question is whether the benefit is worth the 10%. That's pretty expensive.
From a macchiavellian perspective, it does appear that the benefits mostly attach to the founders (unless you are selling products to startups) and the 10% attaches to the company, which suggests that the optimal strategy post-YC may be to fail and start another company.
Edit - Obviously I'm not suggesting killing a good company that hits it big and gets a bunch of traction, but if your post-YC company isn't in that position (and almost all of them aren't, by the way, thanks to the risky nature of startups), you have some very awkward math to do on whether to pivot or shut down.
90% of a big number is a lot better than 100% of a small number. If you get benefit out of YC and your company has momentum, killing it and starting fresh on your own is absolutely not the best strategy.
10% isn't all that expensive in the early stage, especially for a high growth software business where it will be diluted off very quickly in subsequent rounds. If we're talking hardware or research, where a significant amount of time and effort (and possibly money too) has been expended, then yeah, 10% won't make much sense (it still might, based on the exact space your product is in). I think YC themselves say that the best time to apply to it is just after the initial validation (which doesn't work for hardware or research).
That is entirely dependent on how much you're leaving on the table by failing. When gambling, it might make sense to quit while you're up but that entirely depends on the expected value of your next bet.
From a macchiavellian perspective, you also have to consider how much benefit the founder would stand again from having a more successful startup instead of failing.
From a macchiavellian perspective, it does appear that the benefits mostly attach to the founders (unless you are selling products to startups) and the 10% attaches to the company, which suggests that the optimal strategy post-YC may be to fail and start another company.
Edit - Obviously I'm not suggesting killing a good company that hits it big and gets a bunch of traction, but if your post-YC company isn't in that position (and almost all of them aren't, by the way, thanks to the risky nature of startups), you have some very awkward math to do on whether to pivot or shut down.