Its really annoying as a fan that they insist on making a F4 movie that no one wants just so they can hold on to the rights.
The average person wont give a damn about F4 but they might if it was in the MCU.
I mean, the one reason it might not happen is because shooting a film and finishing its production costs money.
If Fox is faced with likely losing money on producing the film or with losing the rights if they don't produce the film, losing the rights might be preferable.
However, the optimal version of events from Fox's perspective means either producing the film and having it be a big, profitable hit or *selling* the rights back to Marvel instead of letting them simply lapse.
And *both* of those approaches require producing the film (because even if they're only looking to sell the adaptation rights, Fox can only plausibly negotiate the sale back to Marvel if it looks like Marvel isn't going to get them back for free).
So the odds are good that Fox will make this movie happen no matter how obviously disastrous it'll be. The question is what the situation will look like after the film comes out (i.e. if the film bombs but the rights are no longer at risk of automatically reverting to Marvel anytime soon). It's equally plausible at that point that Fox could attempt to negotiate a sale or that they could give themselves another seven years (iirc that's what the contract stipulates between films?) to try to reboot the franchise yet again.
