Wow, you're jumping to that conclusion already? As much as I'm sure the three of them are great additions in a lot of ways, none of them has led a product to a meaningful exit just yet (Pinterest, 123andme and Airbnb have yet to exit).
Now their valuations are sky-high, and they've raised an incredible amount of money, but it seems like a big chunk of YC people (people working for YC, not in the program) haven't really successfully led a company to a big exit (IPO or $100m+ cash buyout).
PG: Sold Viaweb for ~$50m
Sam Altman: Sold Loopt for ~$43.4m after raising ~$30m
Anne Wojcicki: Raised $191m, no exit
Ben Silbermann: Raised $1.3bn, no exit
Joe Gebbia: Raised $2.3bn, no exit
I'm sure they're all very bright people, but at the end of the day, these aren't companies that have been profitable or really been sustainable. They're great resources for how to raise lots of money, sure, but are they people who can speak at any great lengths about building a long-standing business?
I don't mean to sound incredibly negative about YC; I want to keep a level head when looking at them and what they offer.