The team was pretty much 100% focused on keeping the game alive as a multiplayer game. And I think it’s a complicated question to accurately predict the behavior of the game when this server or that server goes down — or changes in a way that requires the game to be updated. I definitely can’t do it, I wasn’t familiar with the server infrastructure. Don’t know whether your player profile was locally cached, though I kinda think it was. Can you even get past the main menu without an acknowledgement from My2K? Dunno.
If Steam still supports offline mode, someone could switch it offline, try to launch a different single player game. If it works, try to launch Evolve that way. If that works, then physically unplug the network cable and try it again. Hopefully that will let you eliminate Steam as a culprit, and see how Evolve works when 100% unable to contact any 2K servers.
Edit: I just had a successful test with Subnautica and no network cable. Steam offline mode is still a thing. Now someone just needs to try it with Evolve.