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.
I wonder if it’s because Trump doesn’t want to share the spotlight
That’s absolutely it.
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.