If it's anyone's fault, is George Lucas's. He sold the company. Disney bought the Star Wars package, of which LucasArts was a very small part of. Now, Disney is huge, it doesn't really need another video game development house. And LucasArts wasn't even a well oiled, game-making machine. It was a struggling, leaderless mess who was only developing one or two titles. Keeping it, meant a money leakage that would continue until 1313 was finished, maybe. It's sad that they didn't do that, but also understandable. But also, it was again Lucas fault for handing it over in the condition that it was. Disney inherited all of this, and it was forced to deal with it.
Also, Disney will own all the Lucas IPs, until the end of time (or well, for however long they manage to stretch copyright law, they keep pushing it to protect Mickey Mouse).