keeping their checkbooks in their pockets in the POTUS race.
They are going to trust that Bloomberg is going to keep the economy strong, if for no other reason ... his personal interest, given his fortune.
I doubt Adelson, for example, is going to give 10's of millions to Trump and RNC PAC's when his biggest interest is Israel. He'll trust fellow Jewish Billionaire Bloomberg ... to do right by Israel. No need to drop 10's of millions on dipshit Trump. He would, however, likely still fund the Congressional Races to be sure.
The remaining Koch already doesn't like Trump ... he's probably fairly okay with Bloomberg though.
I think if Bloomberg is the nominee, not only is his presence going to get massively under Trump's notoriously thin skin ... it's also going to hit his campaign funds, perhaps significantly.
Nobody trusts him to not steal what they give him in campaign funds to begin with. Billionaires are generally not stupid people. Many of them will simply look at a Trump/Bloomberg race as a great opportunity ... to save their money. Win/Win contest, basically.
Not necessarily saying I LIKE this reality, mind you. But it's an advantage come November nonetheless.