This assumes a large portion of the game doesn’t rely on servers.

We can reverse engineer those too, by looking at what the game client expects. Its harder, obviously. But far from impossible.

I started writing my own world of warcraft server about 20 years ago by disassembling the WoW binary. I got to the point that you could log in to the game and run around in a big empty world. I even found a couple mistakes in wow's in-game encryption in the process. Lots of teams have gotten much further than I did. There's whole communities who play wow on private servers.

If we can do that for MMOs, we can do that for just about anything. Especially with LLMs. LLMs are incredibly good at this sort of work.

The online portions will be reverse engineered and there will be community servers or the online checks will be replaced with offline stubs. You think in twenty years they won’t be able to do this in minutes for practically nothing using GPT 15 or whatever?

Sure, but that's orthogonal to discs. Nothing prevents a game developer from making "check the server" the first thing that happens when the game on a disc loads.