Disney then proceeded to buy Marvel, Universal only has a finite timeline to the contract at which point they will have to rebrand all the Marvel rides / areas to something else.
I seem to recall him saying a 10 year time frame before that would happen.
I'm sure the Universal / Marvel contract does have a specific term, but it would have to be long enough for Universal to see enough return on the initial investment they made in their parks. How the option years may be exercised is of course another question. If and when that expires I'm sure WDW will take advantage of it.