Eh, I wanna say money. You gotta pay someone to get that patch working. And then tested. And testing, based on my limited experience, invariably creates unexpected issues and costs money companies are not willing to part with.
I initially wanted to say it is a little cynical, but I am starting to think it is just fiscal prudence ( and customer can stuff itself really ).
think their office in Quebec is losing talent too after they enacted that bill mandating French language. English speaking engineers are leaving Montreal.
[1] https://www.techspot.com/news/95177-ubisoft-disable-online-f...