If it happens, this will become the prime example of Disney screwing over guests to make a quick buck.
Knowing Disney, they'll probably spend a ridiculous amount on a retheme and it will take them 10 years to recoup the cost instead of just continuing to pay for the IP.
The timing of this is seems somewhat relevant. Disney could have been wanting to do this for years but never had the opportunity because DHS is barebones as it is but once TSL and SWL are open, they may find a gap to close ToT to make the switch.