I played the first season of their GoT game about 3 years ago, but similarly didn't keep up with them afterwards. I know the Walking Dead series was very successful though, and never would have expected them to suddenly shut down like this.
I agree that the amount of IP rights they paid for must have played a part in this (along with general mismanagement of their projects it seems). Yeah, they probably should have developed far fewer series and focused more on some of their own IP (i.e. Tales from the Borderlands), instead they decided to keep running a number of expensive projects without really taking major steps (tech or notoriety-wise) with any of them.
Meanwhile, Ubisoft on twitter cut to the chase lol (don't know how much of this is just for PR, but I hope some of those guys can take advantage of the opportunity).
@DarkSpawn might be interested in this thread given his avatar.