Devs have numerous options for how to address the SKG initiative. The top three that come to my mind are:

• Release server binaries (along with modifying clients to have a setting to connect to the right server)
• Modify multiplayer to work over LAN (good when the server’s only/main job is matchmaking)
• Modify the game itself to no longer require online connectivity

In the case of live service games, I would suggest option 3 is the most appropriate. If the main gameplay is singleplayer, but it’s online so you can dole out achievements and gatekeep content, the answer is simple: stop doing that. Patch it to all work in-client. And keep in mind that this will be a requirement at end-of-life from the beginning. If it’s an unexpected requirement, that’s going to be a huge development cost. If it’s expected, making that EOL change easy to implement will be part of the code architecture from the start.