No, you don't understand. Trump and the Republican Party are one and the same. On his way out the door, Speaker Boehner said "There is no Republican Party. There's a Trump party." Republican officials at every level of government are terrified of Trump. Why would Trump give that up? If anything, it's more likely that responsible Republicans would form a new party.
https://www.politico.com/story/2018/05/31/john-boehner-republican-trump-party-615357
In 2015, the Republican Party thought it could control Trump. That's what Dr. Frankenstein thought about his monster, too.