During Hickman run on New Avengers, we had these Incursions, where two earths where going to collapse, destroying both universes in the process.
However this could be stopped with destruction of at least one of the Earths before they can collide. Doing so will save both universes, and one of the Earths.
Let´s now assume we have this Illuminati team in the MCU/FOX amalgam. Which are joined 8 hours before the Incursion , 8 hours to decide who is going to pull the trigger and destroy the other earth...to save both universes.
Do you see any of them pulling the trigger to save both universes but destroying another whole earth in the process? Yes? No? Why?
Assume the other earth is just an alternate MCU.
Note : The team is the same in the scan above, just MCU Thor replaces 616 Namor and FOX Xavier replaces 616 Hank McCoy