I'm assuming Bloomberg would run as an Independent. It would greatly diminish votes for Republicans in the US Senate and HOR. I could easily anticipate that in a situation like that the anger would be directed at the Republican Party and folks would vote for Trump and against the rest of the ticket, except for those totally enthusiastic about Trump.
If the Republican nomination is stolen by Bloomberg or anyone else, the party is over. It would be left with those voters who supported Jeb....and there weren't many.