Ubiquitous networking is common in the Unix world, but much less prevalent in the Microsoft and Apple worlds.
At least anecdotally, I'm not sure I can find a whole lot of supporting evidence for this -- the vast majority of the commercial applications I use on a daily basis let you install them on any compatible system that you own. This isn't just a byproduct of "well, they're not checking"; it's usually explicitly written in the license, it happens with programs that make you enter license codes they validate before running, and notably, it's very explicitly the model of the Mac App Store. Sometimes the license says only one copy of the program can be in use at a time without a site license, but for individual use that's generally fine in practice. (I haven't seen a program that's actually annoying enough to check for running copies of itself on a LAN and shut down if you're violating the license in decades at this point, although I'm sure they're still lurking out there in weird niches. It sounds like something Autodesk software would do.)
Anyway -- maybe running programs remotely using the Xserver model never took off in the Mac world, even after OS X, because there was no prohibition against just installing the software on multiple machines? In practice, it's not something I've missed very often, I admit; while I sometimes like to edit text files remotely, that's not something that feels like it would really be improved by this model over using a local editor that can open files over the network. (Edited to note that I'm not suggesting there aren't still valid use cases for X11's server/client model! They're just not ones that have impacted me; if they did, I'd run XQuartz, which I don't love, but it'd probably get the job done.)
I believe that latter condition is actually true for Microsoft 365 Personal[1], too -- it's tied to your Microsoft account, and the one "seat" you're buying is that user, regardless of the number of devices you have. Business editions tend to be licensed differently.
[1] I know that looks like I got the name wrong, but apparently in April they changed "Office 365" to "Microsoft 365."
Individual use (there's a funny story here) doesn't really matter; what matters is groups, corporations, with tens to tens of thousands of users, and yes, Autodesk is an example (and GitLab (https://about.gitlab.com/pricing/), sort of). Things that make X necessary and useful are typically, something that you absolutely need, that requires custom support and big hardware, but not something that everyone on your staff needs all the time.
Funny story: At one point, a security researcher realized you could run a program through an instruction-level compiler, reordering operations without changing behavior, so that the machine running the program would broadcast RF signals containing the program's license number. It wouldn't really do anything for single machines because the signal was too weak, but if everyone at a company were using the same license for program X, you could drive around the neighborhood with a van and pick that fact up clearly.
Microsoft was completely uninterested. If it would not prevent every individual from pirating even one copy, they didn't care. Which may be why I recently typed in a twenty-odd character string into my new gaming machine.
No. :) I tried to be clear that I was thinking about individual licenses rather than site licenses, but might not have been, and you're absolutely right about corporate site licenses. Apple's App Store is designed for handling individual licenses -- they're tied to Apple accounts, not machines. (With the asterisk that this isn't necessarily true for iOS devices which can be managed by your company, and there's a whole different way of managing those, but companies I've worked for haven't used those.)
I'm not sure I knew Microsoft was still requiring license keys like that for Windows, but I suppose I shouldn't be surprised.