If it's a game like an MMO (which several on that list are) they'd have to publish the server software in order to avoid fully killing the game. And to publish the server software that was only ever expected to run in their own datacenters they'd then have to publish documentation, dependencies, etc. and this is all assuming that it can be contained in a single installer for a single machine without relying on additional services they host, and assuming it has reasonable system requirements for average users to self host.

That's also assuming playing an MMO alone/with only 1-2 people doesn't suck. Play some 2009scape single player without adventure bots. It feels lonely as all heck

Plus there's all of the legal and PR hurdles to ensure you're not exposing yourself to undue risk.

Basically a million reasons for a company to not spend a thousand work hours ensuring their crappy MMO (I've tried out a couple of the listed MMOs, they were unsuccessful for a reason) can continue to be played after they've divested from it

[–] [email protected] 6 points 2 weeks ago

Licenses and middleware can be chosen more proactively to preserve and distribute the server if they know during development that it's a requirement. There are tons of people who functionally play MMOs single player already, when the server is already running. And I play a 12 year old fighting game that's easily able to coordinate 20-100 people to play it multiple times per week with nothing but Discord; there's no doubt in my mind you'd be able to get 40 people together for a raid on a private server.

[–] [email protected] 1 points 2 weeks ago

The other answer from @[email protected] already covers most points, so I'll just a few things:

Most game servers out there are already built in a way to allow for easy deployment. After all, devs have to have way to test changes, so being able to run a small server locally for debugging purposes is hugely beneficial to development.
I also can't imagine that there's any game server out there that shouldn't be able to run on a single system. The heaviest one game I can imagine is Minecraft, due to the whole open world terrain generation, world streaming and physics calculations, and even that can be run off a Raspberry Pi for a small number of players.