I live in NYC and have raised capital/am part of social networks of founders in NYC. I have first hand experience with this, I understand the game really well.
I'm being a little cagey because I don't like to generalize in public forums.
In this case, what I'd say is that Ivy League schools both recruit and attract certain people.
> The schools absolutely are gatekeepers.
To put weight behind that statement, we'd need to somehow believe that someone who can attend an ivy league school, when attending a less prestigious school, is substantially less likely to find VC money.
I personally believe that such a person is attracted to an ivy league school, such that I would argue that someone who is likely to raise VC money is more likely to attend an ivy league school. It's not that the schools are the gatekeepers, it's that if they change their admittance criteria, the "minds that think alike" will attend other schools, and then those other schools will get a reputation for their grads gobbling up most of the VC.
IE, a certain kind of person is likely to raise VC, and that certain kind of person is likely to attend an ivy league school: Correlation does not imply causation.
Dude just go look at the founders at ycombinator, huge percentage went to top schools. They only interview them for 10 minutes. Without some kind of proof of being able to run a startup (MVP and traction), capital is allocated based on education.
But that doesn't prove your point. Plenty of startup founders raise funding without an Ivy degree, or a degree at all. Most people without a degree, however, don't try to raise funding, whereas more people from 'prestigious' schools see it as an option.
The schools absolutely are gatekeepers.