If anything, the valuation of a YC session has to have risen over the past couple years, because the alumni network is so huge. Meanwhile, the YC terms don't appear to have gotten less favorable. This point pretty much has to be the opposite of true.

(NB: and I'm a YC skeptic).

Why are you a YC skeptic? Is it their investment model or the kind of companies they fund or something else?

I don't think you can count 'rejected by YC' as a 'negative experience'. It's pretty much the definition of 'non-experience'. It's like saying that the department store experience was bad because they wouldn't sell you a lawnmower at half price when you asked them to.

I was rejected by YC a couple years ago, and I mostly enjoyed it (I loved talking to the AppJet guys).

The fact that I didn't build the company I was pitching is prima facie evidence that I agreed with their assessment. (and in retrospect, I wasn't the right person to do that company and you could hear it in my voice)

That's how I'm viewing it. If I get rejected, that should be motivation to build the company I want and prove them wrong. The odds of being selected are low. That shouldn't be considered a test of you or your idea.

They currently have startups for which things would have to go horribly wrong for them to not exit at $100M+ (Dropbox, AirBnB). Its unreasonable to expect an exit that large in the time that YC has been around. That would be an extreme outlier (think YouTube).

Startups are what the founders make of them. YC is just a stepping stone.

If you got rejected you never were in a position to make any negative experience claims because you have no experience.

I don't think YCs goal is really the big exit on their companies, but helping more companies get to the next stage of VC and to this end they seem to be quite successful.