That's part of it. But it's linked to another reason for his first election. And that is the mainstream media. The--ALL of them, far as I know--quickly realized he was FABULOUS television! His tweets, his rallies, his interviews with the MSM and with fringe publications alike sucked in millions of viewers daily. The cable networks thought they'd be rolling in money.
They found to their delight that they'd underestimated. Trump sucked all the air out of any room he entered. The media cheered him on as their ratings soared.