I don't know about the requirements; I did upgrade from 7 to 8 (while also replacing a hard drive) and then to 10 (because I wanted Bash for Windows). It works very well, but my computer is a desktop, and I did pay a bit for it back then. Meanwhile, a lot of computers had Win7 preinstalled, and I wouldn't call most of them powerful. Hence the caution - OEMs don't give a shit, they'll happily sell a laptop that can barely lift its own OS[0][1], so if you upgrade that kind of equipment you risk basically bricking it.

[0] - Just recently I've been "fixing" such one laptop for a friend of my mother - it was barely strong enough to lift its own Windows installation. I made it much more useful by just replacing the RAM die with a one I pried off a broken laptop that serves as an "organ donor". Hell, I found getting moar RAM to be a quick solution for most of the lower-end laptops that get "too slow".

[1] - this happens for mobile too (as I experienced first-hand), so my rule of thumb is that in terms of computers and smartphones, buying cheap is worse than not buying at all

Requirements don't enter into it - and even the requirements from Win7 to Win10 didn't rise that much. I could live with slightly hungrier but better OS. Emphasis on "better".

They only just moved them up. 10 I've found runs better on older hardware than 7, it's was the same story for 8.

They just increased them. You now need 2GB for the 32-bit version of Win10, iirc. That's the only change, though.

What would someone with 2GB memory do with a computer? State at the desktop? Once you start opening tabs, Firefox and Chrome can easily take up 4GB memory if available.

If available. If not, you'll quickly learn to not open 50 tabs (it's not like you're actually browsing in all of them). Had to work on such a PC out of necessity, and :5 tabs should be enough for everyone" ;)

But seriously: 2 GB on Windows (7) is still usable, even though not entirely comfortable. (Of course, on LXLE, 2 GB is a lot, but that's an entirely different can of worms)

Isn't it only 1.5GB that'd be left for user apps? I seem to recall 32-bit windows only had 3.5GB total accessible for some reason.

32bits can only address max 4gb ram and I think video ram was counted for or some other overhead. With 2gb the 32bit maximum should have no effect.