Can an email go 500 miles in 2025?

I really wouldn't have predicted the extreme amount of centralization, and arguably unnecessary centralization, that we have today for things like university email and web servers. Even 20 years ago when I was in college, the servers I interacted with including email, were all in our school's /16. They did have software packages for LMS and stuff, but those were mostly deployed on-prem.

Today the websites are hosted on third party cloud servers (my school's main website is some company that hosts your Wordpress or Drupal site so you don't have to) and the email by Microsoft or Google. Same for every school it seems. I guess the IT department that used to run all the infra is now probably just a few people in charge of ordering new laptops for faculty/staff when they break, and replacing Wi-Fi access points every 5 years.

You answered your own question. IT staff is expensive, a SaaS subscription less-so.

Spam is another reason most places don't bother with selfhosting email now. Big providers like GMail aggressively filter unknown servers so if you attempt to host your own and don't setup everything perfectly (or even if you do and you trigger their filter ban threshold) all your email will silently fail to deliver or be blackholed to the Spam folder for the largest email providers and you might never find out or have a way to get them to reconsider.

You totally could make that prediction just by thinking about a number of schools in the world, a number of /16s in ipv4 and a rate of ipv6 adoption.

Typically that "IT department" was just a few CS teachers, who assigned some slacking students creating a webpage as a homework, and replacing a bad memory in a server computer as a lab work, and then gave up when that become impossible.

You, sir, obviously have not dealt with enterprise SaaS subscriptions

Meh. Decades ago most universities realised it made sense to separate "run the IT infrastructure that the university runs on" from the CS department, and after that the university IT department followed the same trajectory as the IT department of every other large institution. It doesn't really make sense to run your own email servers any more if your core business is a paper merchant or steel mill or whatever, and it's the same for universities.

I'm sure the same thing happened with e.g. electricity - at first people in the physics department ran their own generators, then at some point the university was using enough electricity for day-to-day stuff like lights that the main generators moved to being operated by the facilities department, and nowadays the university just gets their electricity from the local wholesaler like every other big organisation and probably doesn't have a whole lot of transformer expertise in their maintenance department.

Something I faced at multiple companies before Google and MS took over was that malware would get on your mail server and start blasting out spam. And then you'd find yourself on a bunch of blacklists thinking they made a mistake but it's because your server was actually spamming.

Yeah that's another issue, you could correctly wind up blackholed and not really have a resolution to restore your status when you resolve the issue.