Per the official Stop Killing Games FAQ: https://www.stopkillinggames.com/faq (apologies if formatting ends up looking weird)

Q: Aren’t you asking companies to support games forever? Isn’t that unrealistic?

A: No, we are not asking that at all. We are in favor of publishers ending support for a game whenever they choose. What we are asking for is that they implement an end-of-life plan to modify or patch the game so that it can run on customer systems with no further support from the company being necessary. We agree it is unrealistic to expect companies to support games indefinitely and do not advocate for that in any way. Additionally, there are already real-world examples of publishers ending support for online-only games in a responsible way, such as:

‘Gran Turismo Sport’ published by Sony ‘Knockout City’ published by Velan Studios ‘Mega Man X DiVE’ published by Capcom ‘Scrolls / Caller’s Bane’ published by Mojang AB ‘Duelyst’ published by Bandai Namco Entertainment etc.