Let alone USB. During my training, there were lots of desktops running Windows NT 4.0, which did not know USB. By the time I had already become so used to copying data back and forth with a USB thumb drive (even though back then their capacity was still measured in megabytes), that it became fairly annoying to walk up to some computer, plug in the thumb drive, then realize this machine is running NT 4.0, not Windows 2000, cursing, then looking for another way to get some piece of data on that computer: Usually put it on some other machine copy it over the network.
Ah, those were the days... ;-)
This doesn't add anything, because contrived or not, it doesn't answer the question that was posed: "What does modern Linux do that Solaris from the 90's did not, that it requires 50x more memory?"
It hits the first part of the question, but not the second part. We could add wifi to a 90s OS without severely inflating the memory requirements. My Nintendo DS (with 4MB RAM) "seamlessly connects and disconnects to wireless networks", after all.
You could easily answer the question with a sensible, non-contrived answer, and I'm not sure why you didn't.
Just booted my laptop (FreeBSD -current amd64, 1366x768 display) and started X: only 204M "Active" memory. Of the 204M: 60M is syncthing, 39M compton, 31M Xorg, 11M i3bar, 11M polkitd, 10M i3, 9M dunst, 5M wpa-supplicant… Not counting syncthing that's 144 megabytes. I think that looks reasonable. You can go lower and optimize for low memory (no polkit, no compton — 94M) or go higher and optimize for usability and fancy UI features (install gnome :D)
Anyway, this is is just 1 contrived example of something modern OSs do, and that OSs from the 90's didn't do.
Sure, there's some bloat, but a lot of it is the "Mozilla kind": "Mozilla is big not because it is full of useless crap. It is big because your needs are big".