Linux

This is why Ubuntu was such a big deal when it came out, it was one of the few where things more or less "just worked" without having to chase proprietary or reverse engineered drivers down

I remember that even a graphical Installation was rare amongst distress which is why I briefly used Mandrake as one of my first.

Yes, Ethernet, not Wifi, which would have been understandable.

Back in the day there was 'software NICs' on the market which required separate (driver-ish) software to do anything. Also there was RTL chips which required propietary parts from a driver and all the fun stuff. On wifi it's still a thing now and then, but everything works far better today, and it's at least partially because hardware is better too. Of course even in late 90's when ethernet started to gain traction you could just throw something like 3c509 or e100 to your box and call it a day, but standards were far less mature than they're today.

Short answer: Enterprise bullshit and Adobe.

On the home computing side, I can't think of much that has specific OS requirements besides gaming and DRM'd 4K streaming. For better or worse, most desktop apps nowadays are glorified web sites. It's a different world today than it was 20 years ago.

On the enterprise side, nah. Way too many vendors with either no Linux support or shitty Linux support.

Microsoft is working hard to shove "New Outlook" down everyone's throats despite still not having feature parity with old Outlook. Nobody in my company will want to use it until it is forced because we need delegated and shared calendars to actually work. And then there's the "you can take my 80GB .pst files when you pry them from my cold dead hands" crowd. Advanced Excel users are not happy with the web version either, and I don't blame them.

CAD software.