I bet Universal to some extent wants to keep Grinchmas special, though. If you had a year-round Grinch attraction in the form of Mt. Crumpet... well, there'd be a lot less incentive to visit during the holidays, live action-prosthetics version of the Grinch notwithstanding.
I hope this Lorax ride will be a dark ride like Cat; Islands really needs more family rides, and both parks could use more animatronics.
...also, how the hell are they gonna pull off a Lorax sequel...?