I think it’s totally fine for a company to shut down the servers for a game…
…as long as they have a public tool to host your own server, free of any restrictions. They can also stop selling the game, but they can’t shut down the distribution for people who already paid for it, unless they straight up host it somewhere public and call it shareware from that point onwards.
Any other alternative is crazy. Imagine you buy a music vinyl, then 5 years later some Sony executive knocks on your door and says “hey you know we are shutting down, so imma need that disc you’ve bought I’m going to shatter it right now thanks”