You don't own the game, you own a license to play it for however long the publisher wants. Whether or not it is legal really shouldn't matter, it should just be done as a matter of course for such games.
If it has a buy button for game xyz you should assume you’re buying the game, not a license, even if the fine print says otherwise. For multiplayer games it would probably be ok to not perpetually run the servers, for single player the server isn’t an aspect that is crucial to the functioning. There may be an issue with how long ago the purchase was though.
[1] Okay fine you can but nobody who buys Skyrim thinks they are buying the rights to the whole Skyrim media property. But hey, I hope I'm wrong and you all owe me lots of royalties.
If they’d change the button and add an explanation that the license can be revoked at any time without notice or reason, then my argument would be invalid, but users might not be willing to pay as much any more.
Edit: because they now openly know the significant terms and know they’re potentially being screwed. It’s already bad enough to pay full price without the ability to resell or pass on (not sure how games are right now, but that’s why I don’t use a kindle, along with it being tied to my other Amazon account and everything that goes with it)
https://www.lexology.com/library/detail.aspx?g=f5b1193c-f423...
That ruling just states that it is not a copyright breach to decompile a program to correct errors.
It does not grant a carte blanche against other laws. DRM circumvention laws are separate offenses and are not overridden.