What are the odds that Trump will decide to kick Vance off the ticket?
I wouldn't put anything past Trump. My sense is that Trump would say or do anything drastic if he wanted the spotlight and felt it was necessary to reclaim control of the media narrative.
However, on that note... the folks on CNN yesterday were making a big deal about the fact that Trump hasn't done many rallies recently and didn't have any public appearances scheduled for almost a week, while Harris, Walz and Vance are appearing almost everyday. At first blush, I thought maybe it might be that his age is starting to show, dare I say... cognitive decline? His last several speeches and interviews lately have been more and more off-the-rails, even for him.
However, to be fair... inasmuch as you would want to be fair to Trump, which... meh... it did occur to me that he did recently survive a literal assassination attempt, and the Secret Service hasn't even sorted out the investigation yet (they were having Congressional hearings on it today). So Trump and his camp could be excused for being a little bit more cautious about scheduling his appearances.
Which brings me back to JD Vance. As the running mate, Vance really has been carrying the water for the campaign this week, so I don't think Trump would be too keen to dump him at this point. He seems to need him to carry the load right now.
That said, Harris seems to be gradually taking a clear lead in the polls. On rcp She had been ahead in every national poll so far this month until today and was building a lead. That is until today when the Rasmussen poll swooped in... to do what it always does... prop up the Republican candidate. Also, seemingly out of nowhere, CNBC also released a poll (they apparently hadn't released any for a very long time) that was in Trump's favor, The CNBC poll was nowhere near what Rasmussen was though. In any case, Harris still has the lead on rcp by 0.5%. We may see soon how the Republican-leaning Harvard/Harris poll affects the rcp averages.
https://www.realclearpolling.com/polls/president/general/2024/trump-vs-harris
BTW the FiveThirtyEight ("538") polling aggregator has Harris up by a full 2%. 538 does not acknowledge Rasmussen currently though. They did however include the recent CNBC poll in their averages.
https://projects.fivethirtyeight.com/polls/president-general/2024/national/