I suggest you are both right and wrong. Don the Con is not mad like George III, for he appears to have been psychotic (the technically correct and polite word for "crazy," for stark raving mad). The Donald is not psychotic, but he is severely neurotic, IMHO. The character flaws you list (incompetent, unprepared, incurious, etc.) are just some of the symptoms. There is a difference between the delusions of a psychotic and Trump's delusions. The core difficulty is that when confronted with a psychotic, most people recognize the condition as mental illness; but with neuroses, opinions vary.