Bloomberg got ZERO delegates in Iowa.
Suppose the Democratic party sees Bloomberg as their moderate salvation and they give him the nomination in a brokered Convention. Then Trump can make the case that the Clinton's sold the plantation to Bloomberg. That voting for Democrats is like choosing hall monitors on the Titanic. It might give the doomed a sense of control but there is no chance of influencing the final outcome.
That is, Trump will package the Democratic brand as an entity that buys-and-sells voters as chattel. To identify as a Democrat and to vote as a Democrat is to willingly sell yourself and your children into bondage where you have no agency over the future.