Access and valuations. Although YC does much better than other incubators in terms of outcomes, the batch sizes are quite large these days and the best deals are oversubscribed before the batch even starts. There's a lot of money chasing deals. So unless you have a solid reputation, it's hard to get started.

Obviously, you can overcome that by just spending the time, building dealflow, etc, but it suggests that new angels won't get access to the 1% deals. One of my batchmates was Cruise Automation which has had a spectacular trajectory. I don't know for certain, but I suspect Kyle wouldn't have been willing to take $10k from me. :)