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.