There's a great initiative going on right now trying to hold Ubisoft and other game publishers accountable for shitty practices like this by trying to petition governments from a few different nations to create legal protections for people to continue to have access to their games they purchased after the publisher decides to abandon a game. If you live in an EU country especially, you might be able to help sign a petition still: https://www.stopkillinggames.com/
There's a bunch of petitions and actions possible on various parts of the world. It's not just one meaningless online petition but a comprehensive plan to bring this to attention of various governments worldwide. Keep an eye out, there might be something you can help with in the future depending on where you live.