A disc alone isn't sufficient for reselling without anti-online-DRM policies, but a disc is basically necessary to allow reselling still.

I remember this was true of MMORPGs in the 00s. Not saying that justifies the state of things of course.

It’s somewhat fair for multiplayer only games. Preservationists want the right to stand up their own server and that would be nice, but I get it.

However for games with a real single player component, or ONLY a single player component, there’s no excuse other than they can.