Trump has experience with Reality TV, and he knew that the characters who always survive until the end; the contestants who don’t get voted off the island or out of the house; are the ones who are the most controversial and outlandish. The characters viewers ‘love to hate’, the ones everyone watches week after week because no one knows what they will say or do next.
He understood, correctly, that the presidential campaign was essentially an entertainment program, and he created the most watchable character on the show.