Oh I definitely agree that whatever replaces the Simpsons Ride for the long term, the building is coming down. I'm just saying with USH having so much in the Pipeline (F&F, Bourne, DK, etc) plus the contract for Simpsons ending the same year as the LA Olympics starting, there's no way they're going to have a legitimate replacement for Simpsons open within five years. Unless Bourne is replacing the Simpsons. They want all the capacity they can get in this small park and I seriously doubt they want that area closed off for construction once the LA Olympics start.
You're probably right, they probably won't do this. Once that contract expires and the Olympics starts, they could however buy a little more time for a more substantial replacement if they pulled a Captain EO and said "Guess what's back for a limited time!" The biggest work would be reskinning the cars back to the DeLoreons. Other than that and replacing the Krusty Head with a new sign, everything else could just be a simple paint job while adding some posters or random props on hand in the preshow rooms (Which wouldn't need to be exactly how it was). While that would only take a few months, the queue TV and IMAX footage can be changed virtually overnight. Heck, they could probably get away with just keeping the building blue. Just repaint the beams and the front and you're gold.
Again, this is all an idea and they probably won't do this, but if they're crunched for time and a substantial replacement isn't an option before the Olympics, I think this could be totally doable placeholder ride for 2-3 years. I can't image this would cost a whole lot to convert it back and this would be extremely marketable. Think of how many folks in their mid-20's+ who would kill for at least one more ride and all of the youngins who never had the chance to ride and would love to experience it. 2027 would be a great year to do this since it would be right before the contract expires and it would be the 20th anniversary of the ride's closure.