I don't think saying 80% or so of YC founders didn't go to top-tier schools means schools don't matter- I haven't seen the data on the applicant pool which is obviously relevant to this, but to me it seems like if 20% are coming from top-tier schools that's a much higher % than the pool of say, HNers that went to top-tier schools.

Of course this could simply be because the applicant pool has 20% applicants coming from top-tier schools and there is no bias in who is picked, but just saying that "80% or so didn't go to top tier schools" doesn't mean much without context.

And of course, in theory those that went to top tier schools should make better candidates, but that doesn't necessarily mean they have an advantage in the interview process because they went to a top tier school, rather that person is just more likely to be a motivated/intelligent individual.

(All generalizations up for debate, of course- merely pointing out that the 80% figure isn't exactly solid evidence for the point).