Universal also doesn't have the motive to right now towards getting theme park Marvel rights for WDW due to their actions.
Universal updated two of its Marvel attractions this decade including the Incredible Hulk Rollercoaster in 2016. You do not do major updates to theme park attractions if you want to get a rid of the IP rights. The other thing is Universal started Marvel Character dinner on December 7th of last last year.
Universal wouldn't start Character meals in December last year if they wanted to sell the theme park rights.
Here is one of the sites that mentioned the Marvel Character Dining.
https://www.insideuniversal.net/2017/12/marvel-character-dinner-coming-to-islands-of-adventure/