My prediction is that due to the damage that Aramark are doing to the perception of F&B at park - they will eventually need to go back to franchising branded vendors in order to encourage guests to spend on food again.
Your average guest has no idea Aramark are running the show as opposed to Towers, all they see (and taste) is overpriced awful food. Even if Merlin end the contract and go back to in house, it would take time and money to restore service to a decent standard.
By inserting known brands back in the parks you can achieve this much quicker, as guests know what they are going to get with a McDonalds or KFC for example.