I would guess that they just decided it's time to change things up. Every year they have controversies over the Bill & Ted show and they probably are tired of dealing with it and the licensing agreement is probably up so they decided not to renew.
And to further add to the point, I would imagine what they could actually do; is that they can do seasonal shows in that theater. I would imagine the set of FFL/WWW gets taken down in the process of things, but that theater would allow the possibility of a new halloween show to be made for that time of the year, or to relocate How The Grinch Stole Christmas to FFL, and having expanded seating there. There are plenty of opportunities that they could do with a possible seasonal venue for USF, especially as USF is used for HPC, HHN, Mardi Gras, Holidays at Universal, Rock The Universe, and so much more.