op i know you're probably talking about like, video games, etc, but this is also critical for research science - my lab has so much abandonware, either because the company's out of business, or the company decided to not maintain it, and it's a fucking nightmare. we have two windows 95 computers that are CRITICAL for performing experiments/data analysis because the software needed is abandonware. one of the main roles for a guy in my lab is to maintain these little dinosaurs because if they go out, we lose access to ~20 years of raw data for research. part of why is that these companies also make their own file types, and make it difficult-to-impossible to convert those file types without their specific software. by habit, i convert all research files to more generic versions (txt, pdf, tif, etc) so that i minimize risk of losing my shit, but some stuff can't be converted.
for example, we have a microscope that is perfectly functional, good microscope, but its software is abandonware because the company refused to maintain it. the company is still in business, still makes essentially the exact same software, but they made all of the old tech incompatible with new software to force people to buy the new microscope tech. it would cost a quarter million dollars to replace this microscope. this perfectly good microscope.
so like, i know a lot of people look at the original post here and go "well op just wants old video games to play" (which is valid! games companies should not be able to push shit to abandonware and then close it off) but also this is critical for like. biomedical research. if y'all had any idea how much basic infrastructure built on science relies on shit that is technically abandonware, you would probably be horrified.