The aim is often not to succeed to creating a breakaway party, it's to threaten one credibly enough which the party must move towards in order to stop it breaking away. I would suggest a problem however is that it needs to heavily involve a grassroots component. Top-led breakaway factions have a habit of falling flat on their faces.I know there's also some discussion of a lot of the GOP(or former members) who very much despise him openly talking about forming a new Trump-free Republican Party. Which wouldn't win but would likely have a spoiler effect of drawing off more moderate conservatives to vote for them.
The issue of donors in an interesting one - they can fund an astroturf movement easily enough. I get the feeling that neoliberal donors have helped breed the monster that became Trumpism, and they're taking a look at the protectionism and anti-elitism that's against their agenda and thinking that monster needs to be put down.