The result is that humanity will progressively become worse at math because no new student will have had to take the steps to figure things out themselves. How long it is possible for society to rely purely on AI math results remains to be decided.
This seems to assume a finite number of interesting math problems. Good mathematicians should be able to learn new techniques from the LLM generated proofs.
Maybe most people don’t find it depressing. That takes away nothing from the experience and feelings of those who do.