That may be what you want but that's not what stop killing games is about. You can't ask for the life plan of some software because companies will simply say that they plan to keep it up forever and then later say "we can't keep it up anymore! Too expensive! We go bankrupt uwu"

You can't demand either from them that they upkeep a game fo as long as players exist.

The initiative is about making companies guarantee that if (when?) the games EOL arrives, then they release whatever resources are needed for players to continue using what they have paid for.

If you are looking at it that way, you should not buy any game with an online component. Every single one of those will be gone at some point.

I know you are asking the "when" but that can be difficult to assess for a company that is built on pure profit.

Which is why the initiative is more about being able to make your own servers for these games, not about forcing companies to keep their servers alive indefinitely.