they need to open the code enough for fans to keep the game functional
That makes sense. Another commenter pointed out that even for defunct MMORPGs people were able to spin up their own servers to keep the game alive. If companies are forced to provide something to help that, it's already a win.
I'm not hopeful Canada would be able to pass legislation forcing companies to open source things, though. Maybe if this was the EU lol our track record of fighting tech companies hasn't been pretty.