What are the odds that - if it happens - the whole event goes off the rails as Haley tries to do traditional political campaign stuff and Trump just keeps up his incoherent deranged rants and says nasty things about her?
To be fair, imagine the harassment you and your family would get if you did something like that... Especially if you were already well known and not liked by his base
I would literally fear for the safety of her children
Vance grabbed the spotlight after his nomination, and that would have been a sin enough, but he was also extremely unlikeable and weird. He probably can't show his face in public without Trump personally approving it, and Trump no longer has the attention and energy to follow his own schedule, much less micromanage Vance - hence, no Vance.