there’s nothing stopping companies from releasing alternative servers when their main servers turn off
Aside from the fact it's proprietary stuff they own... you can't just mandate that a company must release stuff they own to the public. They own it, they can do whatever they want with it.
manufacturers are under tons of regulation when it comes to support and availability of replacement parts in various industries.
This is the far better parallel to draw imo, and has the best chance of meaning anything.
Except for the fact for most games the online play is an extra feature and not the core game. And thus all game devs have to do is argue that "the game still works in offline play" and this won't apply to those games anyways.
Companies just decided not to do it anymore because they can make more money with their current strategy.
Oh god no, it's way more complicated than that.
Modern game servers for major games are simply just not designed to be run locally bare metal. They're often in the form of complex stacks of multiple moving parts, shit like entire k8s deployment stacks with like 12 distinct resources, many of which might be tightly coupled to implementation details.
Such that even if they release that part public, it still wouldn't work because it depends on other pieces that literally don't exist anymore.
A great example of this is simply any login process.
It's super likely they have an auth server they run that you login to.
They use that auth server for multiple things, not just this 1 game.
They release, say, v2.4 of their game server program in 2025, it's tightly coupled to the auth server v1.7 api.
It works for about 4 months before they update to fix some stuff on their auth server, now their auth server is v1.8 annnnnd...
Now that v2.4 copy of your game server stops working cuz it's not compatible with v1.8 of their auth system, so it's now just dead.
You can't mandate they keep updating their old code on a game they don't support anymore.
So... you're fucked anyways.
You can't mandate they release their auth server cuz it's still in active use and you really don't want to expose the inner workings of the auth system to hackers for them to inspect.
So yeah, it's just not happening, sorry.
Designing a server to be self hosted is a critical choice you make very very early on in development. If it wasn't designed that way from the start, its useless to ask for a copy of it for self hosting, it will stop working eventually when external upstream apis stop being compatible.