We're about to see the first generation that grew up with a really ubiquitous internet come to grad school age though

I only know about STEM, but I don't think it will make a ton of difference (will report back once I see a few graduate).

What I'm interested in now is whether in the next couple decades we're going to see a Grigori Perelman or Shinichi Mochizuki style extreme outlier produce some result that ends up widely acknowledged to be an equally big deal as what Perelman did, without ever having seen the inside of an university.

I am quite certain this is very unlikely to become any type of trend (it is certainly possible for outsiders to be great, Ramanujan was an outsider after all).

edit: I think a better example of "credentialism" is docs vs nurses. MDs know a lot more than nurses do, but there is a ton of routine healthcare stuff that needs a doc for no good reason, basically. In academia people ultimately just care if you are good or not. One of the smartest mathematical minds I know is an MD, not a PhD (and is an enormously influential academic doing mathy stuff). There is a famous mathematician at UCLA without a PhD, I think.