I think the company should also be required to clearly state the amount of time they'll keep supporting the game and will operate the servers for. If they decide to shut them down early, everybody should be given the choice to either receive a full refund or the non DRMd version of the game + the server software like you suggested.

In general I think all paid games should be required to clearly state the amount of time they'll keep providing feature updates for, as well as support for new hardware, major bug fixes, and minor bug fixes. Although games that aren't online and just reach EoL are still playable for quite some time, eventually there'll be some breaking operating system or hardware change that will force the use of a virtual machine, compatibility software, or other types of emulation to keep playing. That might not happen for 50 years, at which point you probably don't care, but still. I'd give more leniency to indie Devs and games made as passion projects, though.

Although obvious once you think about it, I don't think most people realise or even think of the fact they will eventually not be able to play the game they're buying. And these mega companies need to stop making games they dump 6 months after launch.