Donald Trump has been a no-talent ass-clown his entire life. But he used to be a success. Now he's a failure:
But Trump seems to take this unusually personally, perhaps because he has always recognized the power of the media to craft his image, and so masterfully manipulated it in building his business legend and his presidential campaign. Now he can’t seem to catch a break from the press.
The man didn't forget how to manipulate the press when he became President. What changed is that he went from being the kind of person the press flatters--a rich person--to the kind of person they hate--a politician.
UPDATE: Jon Chait puts it well in "Trump Thinks He's Great At Being President":
Trump, as many have noted, is the world’s highest-profile case of the Dunning-Kruger effect, which is the phenomenon by which incompetent people are unable to gauge their own competence. Of course, Trump is not bereft of talent. He mastered the technique of using the media to raise his profile, flooding the news with arresting quotes and tidbits and scandal, turning the ordinary heir to a real-estate portfolio into America’s most famous rich person — a branding triumph that he leveraged into a lucrative licensing operation, some outright swindles, and, most crucially, a television show in which he played a brilliant executive.