I read the proposal.
As a software developer, yes you are 100% asking that, up to the limit of "within feasability"
And guess what, 100% of the time the answer will just be "no, its not feasible, fuck off" by every publisher ever, so its a total waste of time.
There's no feasible/safe/secure way to hand off your entire application stack for people to run locally, you just have to get over it. The publisher isn't going to give you any kind of access to even an old copy of their auth servers, and basically every "phone home" video game ever uses an auth server, so you are already dead on arrival with this sort of requirement.
There's no way to decouple off from the auth server when the entire online functionality is deep rooted in the concept of you having an account to auth with.