I think a lot of early stage startups look up to YC acceptance as validation, but when you apply at the early stage, you get rejected almost automatically. Too much emphasis on number of users, revenue, etc. So a lot of potentially great startups die before they even see the light of day.

Feedback to early stage startups could encourage more founders to apply and keep going. Otherwise it's time consuming to put an application together.

I have a feeling that the next Facebook, Google, etc. will not be discovered in any accelerator program.