I just don't see the market forces/pressures being there for UFC to buy Bellator. Pride and Strikeforce brought a lot of big names along with the purchase and also eliminated major competitors. Getting Tito and Rampage back plus a few middle ranking guys wouldn't justify the cost it would take to purchase Bellator. They can't do much with their library and Bellator isn't cutting into their revenue like the other organizations do. Unless Bellator starts getting larger and controlling some big name, known fighters (who still have gas left in the tank), they aren't on the UFC's radar enough to be considered for a purchase.
The Jets have won more Superbowls than you have.