I could be wrong, but I don't see the Simpsons license being overly valuable to Universal now.
While the Simpsons are still popular to an extent, they certainly don't have the cultural cachet they had 20 years ago, and I don't think they're adding many new fans. I don't think the Simpsons area is driving very many guests to Universal that wouldn't be going otherwise.
I'd guess the biggest benefit to extending the license at this point would just be not having to spend the money to retheme that whole area.