As someone who works in top-end tech - and hires in bunches - I think it's a little bit of both.
Obviously the kid with a 2.0 from MIT won't beat the 4.0 from, say, Penn State. But I have to be honest - in my experience, the kid from Penn State's resume wouldn't even get to my desk because I wouldn't be looking for him either. If I've got 100 roles to fill, it's a buyer's market and I'll be looking at candidates only 3.5+ from the MITs, the CMUs, the Stanfords of the world. I'd wager the engineers recruited to FANG from MIT and CMU alone are higher in this year's class from every non-California state school combined.
Look, if you get 1,000 resumes a day, you have to whittle them down. Even if the most difficult thing a kid did was get into MIT, you know his baseline level must be high enough to get into that school whereas you can't remotely say the same thing about Penn State. And sure, Putnam helps. Topcoder, internships, projects launched, all of it. But it's just not intellectually honest to say that the opportunities are equal; the kid coming out of State U has to objectively work much harder to account for the difference in prestige. If one could avoid that and all other things are equal, why would someone put themselves at that disadvantage?
For the life of me, I don't get why people are so defensive about this, as if it's a personal offense or like we're belittling their choices. It's not saying that people can't in a few years get to the same level - they absolutely can. First job out of school? Much, much harder. Sorry.
Anyway, OP, this is a pedantic conversation but I hope the point is still clear.