Trump is so stupid he just comes out of the blue with this statement about how the party should get behind Vance.
That is the narrative the Left (and some on this forum) put forth, that Trump is stupid, and by extension, those lackeys who work for him (Like Vance) are stupid and lazy.
Someone has an opinion. Everyone has one. Someone who has never watched Trump or Vance at work, who has zero conception of ANY conversations that have taken place between Trump and Vance, Trump and Rubio, and Rubio and Vance, and believes that Trump is just going to come out and off the cuff, verbally support one of them for the 2028 election. Also brands them as lazy, an empty suit, or whatever the Media wants the audience to think on a given day. Just like that.
I am listing to an excellent video by Bill Whittle who explains best the empty headed opinions of people who brand someone like Vance...or Rubio...or...Trump as a stupid, lazy or...an "empty suit".
It is a very entertaining and contextually relevant video (about 15 minutes long-I changed a couple of words in the wrong tense as Scott Ott was reading the anecdote and got them wrong in his relation of the story): 
LINK: Donald Trump: RENAISSANCE MAN
Here is a transcript that describes an anecdote that was related by RFK Jr. about Trump:
RFK Jr.:"...We started talking about troop strength in Syria and Iran and Israel and Jordan. And he's uh he drew...he's got a very beautiful hand. He drew a perfect picture of the Middle East with all the countries, right? And he put the troop strength on every border of all of those countries.
Um, a friend of mine texted me and said he couldn't believe that I was now working for the stupidest man in America.
You know, I believe he's...I used to believe he's kind of superficial. Now that I know him, um, he [Trump] has like an encyclopedic mind. He knows everything. He knows about music. He has these incredible uh eclectic music tastes. He loves music. He loves theater. He knows everything about sports. He can out talk you and you know everything uh about every sport.
And he's talking at the time to a a podcaster I think is into sports. He knows everything about Wall Street, who made their money, how they made the money, what the deals look like..."