At this point, the rest of the GOP is hoping for this. They're sycophants who probably to a person don't believe in Trump or MAGA at all, but each secretly thinks they're the smart one who will win the game of thrones and be positioned to either manipulate Trump for their ends, take the crown, or both.
Vance, Noem, Haley, Murdoch... the list goes on, but they have all tested and repeatedly compromised every limit they have, thinking "ok, sure, he's a dementia-addled toddler, but this is how I win and I am the smartest person."
They want to put the crown on their own head before Trump's body is cold.
Being un-self-reflective narcissists themselves, they don't realize that Trump is the one entirely using them, this is narcissistic sociopathic limit-pushing 101, they are not original or special freethinkers but exactly the opposite, and their compliance weakens them.
I think you're right but I also think that Heritage and the other rightwing think-creeps area really scared of losing Trump because he gives them a lot of cover with his antics distracting the base and the opposition. If he disappears they suddenly have Vance and a shitshow of unlikable uncharismatic bootlickers because Trump ruined the party and forced out anyone with even a shred of political promise.
If he died in front of 10K people, live on camera, and had a coroner pronounce him dead on the spot, no one there would believe it. It would be an elaborate plan of his to dissappear for a while, regroup, and come back like Jesus, or, an elaborate plan by the damned librels to something something.