Think also about all the finished stand-alone applications which have been discarded because of replacement APIs, or because they were written in assembly. We had near-perfect (limited feature-wise from a 3-decade view, of course) word processors, spreadsheets, and single-user databases in the late 80s/early 90s which were, except for many specific use-case additions, complete & only in need of regular maintenance & quality-of-life updates were there a way to keep them current. They were in many cases far better quality & documented than almost any similar applications you can get your hands on today; so many work-years done in parallel, repeated, & lost. If there wouldn't be software sourcing & document interchange issues, it would be tempting to do all my actual office-style work on a virtual mid-90s system & move things over to the host system when printing or sending data.
Addition: consider also how few resources these applications used, & how they, if they were able to run natively on contemporary systems, would have minuscule system demands compared to their present equivalents with only somewhat less capability.
Outside gaming, ai and big data, aka things for instance my parents don’t use at all, what limited feature wise? Browsers, sure, however my father prefers Teletext and newsgroups and Viditel (doesn’t exist anymore but he mentions it quite a lot) over ad infested slow as pudding websites. Email didn’t change since the 90s, word processors changed but not with stuff most people use (I still miss WP; it was just better imho; I went over to Latex because I find Word a complete horror show and that didn’t change), spreadsheets are used by pros and amateurs alike as a database mostly for making lists; nothing new there. You can go on and on; put an average user behind a 80s/90s pc (arguably after win95 release; DOS was an issue for many and 3.1 was horrible; or Mac OS) and they will barely notice the difference. Except for the above list of ai, big data, gaming and most importantly, browsers. Ai is mostly an api so that can be fixed (I saw a c64 openai chat somewhere) , big data is a very small % of humanity using that and gaming, well, depends what you like. I personally hate 3d games; I like 80s shmups and most people who game are on mobile playing cwazy diamonds or whatnot which I can implement on an msx 8 bit machine from the early 80s. Of course the massive multiplayer open world 3d stuff doesn’t work.
Anyway; as I said before here responding to what software/hardware to use for their parents; whenever someone asks me to revive their computer, I install Debian with i3 wm and dillo and ff as browser, Libreoffice and thunderbird. It takes a few hours to get used to but people (who are not in IT or any other computer fahig job) are flabbergasted by the speed, low latency and battery life. I did an x220 (with 9 cell) install last week; from win xp to the above setup; battery life jumped from 3 to 12 hours and everything is fast.
I install about 50 of those for people in my town throughout the year; people think they depend on certain software, but they really usually don’t. If they do, most things people ask for now work quite well under Wine. I have a simple script which starts an easy ‘Home Screen’ on i3 with massive buttons of their favourite apps which open on another screen (1 full screen per screen); people keep asking why Microsoft doesn’t do that instead of those annoying windows…
Addition: consider also how few resources these applications used, & how they, if they were able to run natively on contemporary systems, would have minuscule system demands compared to their present equivalents with only somewhat less capability.