The only thing you ever need to know about Donald Trump to understand the motivation behind his every word, act and deed:
He's a pathological narcissist, and pathological narcissists need constant attention to survive.
His campaign has never stopped because he needs to be in front of an audience, soaking up their admiration (however maligned) and worship (however misplaced). He's not going to get that sitting behind closed doors in the White House, which is why he's constantly holding rallies, cheerfully preaching the same crowd-pleasing hate to the same cheerfully hateful crowd for the last two and a half years.
Just watch: When he loses the next election -- and he is indeed going to lose -- the first thing he'll do is accuse Dems of rigging the election. Then he can go on Fox News and preach to the rafters how he got a raw deal. Because being a narcissist, he cannot fathom the concept of The Great Donald Trump losing any other way than someone having cheated. And with Fox News' tongue planted firmly up his backside, he knows at least he'll still get to appear on TV every day.