A massive reason must be the security concerns with them, with no upkeep from the manufacturer. And since they aren’t open source (some of the sources are probably lost by now) no-one else can fix the problems. These old drivers are essentially like backdoors into your system. You actually don’t want to have them around.

This is why Linux and other open source software is the only right way. Plug these old devices into Linux, they probably just work due to some hero reverse-engineering them.

We should only buy hardware that has open source drivers. Eventually, the companies should be forced to deliver sources, at least after support ends, and this should be enforced with right to repair style laws.