If Cruz is able to assemble a coalition of 1237 delegates then he will have the support of more of the Republicans than whoever doesn’t have 1237 even if that is Trump. Cruz is clearly better at organizing the crucial ground game and campaign team, which is absolutely essential for a general election.
He'll have the support of perhaps a few hundred insider establishment republicans and lose the support of tens of millions of Trump supporters at the ballot box - either way Cruz and the other Republicans running for office LOSE.