Their massive endowment comes from being selective. Seeing where someone graduated from is an excellent tool that companies use to filter out candidates and that filter is of genuine value to the economy. Hiring people is very very risky, especially new grads. Imagine having to sift through 1000s of potential candidates and not having indicators such as whether they graduated, where they graduated from, how well they did compared to their peers, etc...
It would result in massive inefficiencies and major risks.
With few exception (medical school, some very specialized research), you do not go to MIT if what you genuinely and strictly want is a good education. There is nothing that an undergrad is going to learn at MIT that can't be learned online. There's nothing secretive that MIT teaches that only MIT grads could possibly know about. There is no proprietary research or knowledge that MIT teaches to its students that isn't well established and that other colleges don't have access to. And finally, MIT and most other Ivy league schools and schools in general don't have any kind of specialty when it comes to lecturing or any kind of area of expertise on delivering educational material in any kind of special way; on the contrary most professors are pretty bad at teaching and teaching is not their area of expertise. The textbooks, the lectures, heck even the tests and assignments, are all available for anyone to learn from if they so choose.
You go to MIT because it puts you ahead of well over 95% of the population in virtually every future aspect of your career.
