I don't think it even had to come down to a licensing disagreement. The game had been pretty badly mismanaged ever since Brevik left, they were not making tons of money, and in fact porting the game to consoles was their last-ditch effort to right the ship. That didn't work, and because they had ignored the PC version of the game for so long in the process, most of their pre-existing playerbase was very bored at best or completely pissed off and long since quit at worst. They just couldn't hold on any longer.
With that said, I did enjoy most of the couple hundred hours I spent with it over the past few years. I'm fine with the $50 or so I spent, but I do sympathize with those who spent much, much more, only to see it all come crashing down so horribly.