This is a lesson I learned watching elections in high school; the popular kids who were B or B+ would win over the kid with genius IQ and double 800s on the SATs. In religions, the fewest number attend the most orthodox branch. I think Trump understands this phenomenon, and is using his native Queens dialect to good advantage with the crowds. He certainly knows how to act more polished, and is "caught out" on video speaking with much greater refinement, such as his testimony before Congress 25 years ago regarding real estate law, and his recent press conference at Mar-a-Lago on Super Tuesday evening.
I think you are right.....
His unpretentious manner is a key to his success