It'll likely cost more than "some money", and I'm not so sure that the amount would be recouped easily.
First off, The contract with Universal is pretty straight forward and Universal has most of the leverage. Pretty much the only ways Disney can revoke the rights would consist of (A.) Universal failing to pay the relatively small annual licensing fees, or (B.) Universal neglecting to upkeep the Marvel section of their park to the point that it hurts the brand.....AND then failed to address the issues once Disney/Marvel formally gave Universal notice. Even if Disney decided to manufacture something with their team of lawyers, You gotta remember that Universal/Comcast have their own team of lawyers. Even bigger, Comcast would be much more likely to be up for a big fight than GE would've.
This means that the most likely way Disney will end up getting the rights back is that they convince Universal to willingly give them up. Considering they have most of the leverage, It's likely this would reqiure a nice sized check from Disney to convince Universal to return them (not unheard of since Disney has admittedly bought back rights for Marvel properties from other companies). Of course, This would then mean Universal would need to pay to retheme their existing Marvel section.... And I don't think it would be out of the realm of realistic possibilities that Universal's "nice size check" requirement included whatever the costs would be to retheme Marvel out of the park. So this means that Disney would be paying a large amount to buy back the rights from Universal, and another large sum to basically fund the "re-imagineering" of a competing park's land.
So let's say that they did this, for arguements sake. This brings us to the "easily recoup the cost" section. This is actually the part that I'm finding hardest to find a way that it would be realistic. The problem is that Disney wouldn't just be laying out a large sum of money to Universal up front, But that they would then need to spend a large sum of money to develop and build whatever attractions or themeatic elements they have planned for the Licenses they just bought back. On top of that, They would also be losing the money Universal was paying them for the use of the properties. So in order to "recoup the cost", FIRST they would need to bring in enough profit from JUST the Marvel section of the park to counter the lost pure profit they were getting from Universal. THEN any additional profit could be applied to recouping the money spent on aquiring and utilizing the properties.
New Fantasyland estimates have them spending at least $400mil on that land, with the entire DCA project costing about $1bil. So $400mil doesn't sound that far fetched as a realistic "new land" cost figure. So Figure $400mil for Disney to build out and use the Marvel properties for a land in Florida. But to aquire the properties, They'd probably be charged the cost of developing the replacement for Marvel Superhero Island at Universal.... so that's another land.... $400mil to Universal for their new land. OH! and we can't forget the cost to Universal to convince them to give it up and go thru the trouble of rebuilding/rethemeing their park section. Let's say they are feeling generous and only charging Disney $200mil. Those 3 items alone add up to the $1bil cost of completely reworking DCA. the
Disneyland Resort saw prices jump DRAMATICALLY when the new DCA was opening. We've seen a huge jump of prices in Florida (specifically MK) as a result of New Fantasyland.
The big different here on the accounting side between DCA's cost and the cost to add Marvel to Florida? DCA can logically claim that each park entry, especcially those above the dismal numbers it was pulling in for years, can be directly attributed to the $1bil investment. As such, they can say that all income generated in the park could be directly tied to recouping the investment cost. In Florida however, They can't use that logic. You (and others who bring up the idea of Disney buying the rights back) tend to assume that whatever disney does, it's just a bigger retheme, or just a small land or attraction added to an existing park. As such, You can't make the same logical jump for your park admission being because of the investment. You might be able to apply a small percentage of the admission cost, But you would mostly be stuck using just the income generated within the land itself as your Marvel induced profit towards recouping the investment.
I have a very hard time seeing a single land, by itself, having the ability to generate that kind of profit to "quickly recoup" the cost.
At least with New Fantasyland, they introduced a bunch of new merchandise that ties directly into the new areas and attractions. You also gained a new restaurant that is generating a ton of money in a park that desperately needed more good food options.
With Marvel in the studios, You don't really have either. Disney already sells some Marvel merchandise, and gets a cut of all marvel merch sold at Universal, so the potential for new merchandise which can generate the massive profits is much smaller. The Studios park also already has plenty of food options, so a new restaurant is going to have a much smaller impact on the bottom line than one in the Magic Kingdom did.
I just don't think the beancounters are ever going to greenlight such ideas anytime in the near future. I'm also not sure if Disney would be wanting to set themselves up either for a potential direct comparison between what they do with the Marvel properties in their Florida parks, and What Universal has successfully done with it for over a decade now.