IMO, Trump is doing as well as he is because he speaks what is on his mind, un poll tested, unscripted, un politically correct, un memorized just as all of us 'common folk' speak. He speaks to the people and not down to them. He speaks what THEY are thinking, needing, wanting and does not lecture them or insult their intelligence. His half sentences, incompletely expressed thoughts, one and two syllable words as much as possible, and even the insults are the way most of us express ourselves regardless of our educational level, occupation, etc. He sounds real. He comes across as real.
And he speaks to the anger and frustration and utter disgust so many of us have for elected leaders who do poll test what they will say, carefully script it, memorize it, and repeat it again and again in politically correct language. But once they get elected, they forget all that and do what they darn well want to do which is mostly benefit themselves, i.e. increase their power, prestige, influence, and personal wealth.
I suspect, should Trump somehow manage to get through the political opposition and become the nominee, we will see a somewhat different general election candidate. He will be more precise, more presidential, more acceptable.
And I also suspect a President Trump will surround himself with the best, most qualified, most capable people he can find to advise him, teach him, and administrate a government that is currently out of control. He may be an excellent President or a terrible President, but I can't imagine he would be worse than what we have had. And he, of all the candidates, is the one most likely to implement real reforms and get some positive things done.
And I say that as not a Donald Trump supporter.