They paid $175MM upfront + 35MM for every subsequent movie that 3rd party made for 25% of merchandise rights to a character they already owned, so it's not that out of the question to go up to a bil or 2. It's all about ROI.
Exactly, so they own the live movie rights in perpetuity unless they default or disney pays up. I'm fairly certain they aren't defaulting so that leaves only one option. We can disagree, but the price now would be higher, and like I said, I find it hard to argue otherwise, but you can believe what you want, it's not like either one of us can prove the other wrong since it's a hypothetical.
We have had major talks about legal rights on these threads. I have become a mini expert on it haha. Fox did not breach or default on the contract with Fan4stic. I talked to a lawyer sometime ago and - he didn't have a view on the contracts, of course - but one thing that could be done is taking them to court to try to renegotiate the initial terms since conditions have changed. That would still be a hairy, costly, and lengthy trial that everyone involved would prefer to avoid, with no guarantees of the prosecution winning. Disney's best option, if they want any rights Marvel gave away back, is to pay up.