“if you can obtain a copy of a court order...we’ll do our best to make it happen" Unlike Steam, Good Old Games claims they are willing to transfer accounts to entitled parties after a user's death
Imagine inheriting a GOG account originally registered by your great-great grandpa containing ungodly amount of games you can't possibly play all of them in a lifetime.
To be fair, a lot of GOG games are already for CPUs and OS's that don't exist. Like, a significant amount of their library was meant to run in DOS on a 486. They're pretty fucking good at making that not be a problem.
Like other mentioned, a lot of old games sold right now actually packaged with dosbox. Some even packaged with Wine so it can run on different platforms. The real problem would be emulating current modern graphic stacks but that would be future preservists' problem.
There is VM software like VirtualBox you can use the run older versions of Windows. I’ve had better experience running old games through Windows XP in VirtualBox than directly on Windows 10.