It's a combined weakness of itself and Armada arriving on the scene, I'd say. The people who love capital ships were interested in Epic because it is the only Star Wars game that gives us the option of putting down big ships. With Armada on the scene, the capital ship lovers now have a choice.
And amusingly enough, despite the $100 starter set Armada is the cheaper choice for large scale fleet battles (plus, X-wing's never going to let you put down Star Destroyers anyway).
I most certainly won't stop playing X-wing, and I'll wait and see before I declare I'll never play X-wing Epic (no reason to jump to conclusions when both Armada and the Imperial epics are still half a year away after all). But where the Epic ships were a 100% certain buy for me before, now I'm no longer as sure.
