Trump supporters' blind belief in him as a great businessman and great leader is the result of a sales job similar to that of a charlatan evangelical preacher peddling "true belief" in a false dogma and doctrine. As a matter of fact, you will notice that it is the same group of demagogic charlatans who are peddling both -- (1)evangelicals who are bent on comingling politics and religion to gain power give religious dogma the force of law, and (2) unscrupulous right wing politicians.
Trump is no great businessman. The only reason that he did not do totally bankrupt in the 1980s was that he was bailed out by money laundering Russian oligarchs and corrupt sources, and that all of his real business decisions since were managed by an army of ruthless deal-makers and unethical lawyers. He simply lacks the intelligence and temperament to make good decisions. That also means the image of him as a great leader is absolutely absurd.
My only question to those selling and supporting Trump is: Why do you want to inflict this instrument of destruction on the rest of us?