The only legal way for game preservation is buying exclusively DRM-free games, if they sell DRM-free games the selling physical copies doesn’t matter (you can make your copies at home, save at another HDD, a flash drive, upload to a cloud service you subscribe, or burn to a CD/DVD/Bluray, you own that copy and do whatever you want with it)

I always see gamers praising Steam as if it ever sold physical games and it wasn’t also only renting games, maybe they are dying to give Gabe a sloppy, but can they trust the investors that are going to run the company after him? Steam is part of the same problem.

As for non-DRM-free games, since they are not really selling the game and just giving a license they can revoke whenever they feel like, the moral thing to do is pirate it.