Is it because they weren't capable of making better games, or because Ubisoft gave them a shit budget and shit goals? None of us know the capability of these people. You seem to fall on the side of them being shitty employees and others seem to blame Ubisoft. Personally, the preponderance of evidence given Ubisoft's stock price and recent performance is that their management decisions have been absolute crap lately. They've been picking the wrong approach and it isn't resonating with the public. I can almost guarantee they saw that studio unionize while they were looking at cutting costs and decided that if they were going to cut employees then one of the targets is definitely going to be the union shop.
It's because I've seen shit developers, and activist developers, and shit activist developers as well - so I will not default to assuming that's not what it is either, as some like yourself might want to do instead