ISO-Electoral College creation, purpose, consequences...

No, I'm not Constitutional scholar, nor do I have an expert treatise on the subject to point you to, but I think this one is pretty straight-forward.

The Electoral College is mandated by the Constitution, therefore we have it until an amendment gets rid of it. It's not defined in terms that have any significant flexibility in interpretation, so no mere SCOTUS precedent is going to nullify it.

You can look up the specifics of adopting a new amendment yourself, but suffice to say it's very hard to do. There are two ways to amend the Constitution, but only one way has ever been used, and that way requires 3/4 of the states to approve it. (The other method, by Constitutional Convention, doesn't make things much easier either.)

How the hell do you reach 3/4 approval when that would require a bunch of small states, all of whom benefit from the current system, to willingly give up their extra voting power?

There is a work-around that might eventually kick in if enough states sign on. The Electoral College would still technically exist, but it would end up representing the popular vote: https://en.wikipedia.org/wiki/National_Popular_Vote_Interstate_Compact