DRM is just a thing that authors choose to put into their media. The fact that they do it because enforcing copyright via legal channels is unrealistic is effectively incidental.
If anything, what is necessary to achieve the objective is putting limits on what authors are allowed to put inside of the media they are producing, which is a heck of a can of worms in of itself that I think zealous preservation advocates are a bit too eager to brush off.
- a) patch to game the game playable in single-player mode locally
- b) binaries to self-host a server
would satisfy that requirement.
Note that the details of implementations of any law that would advance the cause are still to be discussed, which is the whole point of the petition.
More on what would be expected and some example use-cases are available in the FAQ of the Stop Killing Games official web-page: https://www.stopkillinggames.com/faq
With always-on-DRMs, server-based multiplayer service games, and even things like exclusive streaming-only video games, even having access to the data required to run what you purchased can be literally impossible.
Completely agree with you, and so does Ross Scott, the principal proponent of the Stop Killing Games movement.
Unfortunately "Video Games are art" is still too controversial of a take so the focus is currently on the customer protection angle, as the road for this argument is already paved by existing EU legislature.
DRM is a whole different kettle of fish that I agree also needs to be solved with all media forms.