1. Disney didn't buy EA.
2. EA has a contract to license out Star Wars odds are its at least a 5 year contract starting after release.
3. As long as EA has the contract Disney gets the money so it doesn't help them to shut it down.
Exactly. EA has signed an agreement that licences them to produce the Star Wars IP and should Disney try to pull the licensing early, it would be a breach of contract that would cost Disney millions. Having bad publicity isn't something Disney avoids, breaching contracts as a standard makes them less appealing to do business with. While Disney can do a lot, it can't do everything on it's own. For example, the next 3 movies will have to be done with Fox, even though Disney has Touchstone. This is due to the licensing. Just like Star Trek must be done with CBS' approval. Disney puts no money into this game, nor does Lucasfilm/Lucas Arts. They just recieve money as part of the licensing contract with creative oversight.