I don't think the primary concern of his voter base was advancing their political agenda. I believe the anger was the whole point, and they got it by the truck loads.
There was no reason to believe that they would get what they wanted policy-wise from a Democrat or from a different Republican candidate. The next best thing is to make all of the bad people angry, which they did get.
It's not like they would've complained if they'd gotten some of their policies advanced, but that was not the point.
The point was that he said things like "kung flu" and it drove the bad people insane. Or "I can't call Elizabeth Warren Pocahontas any more because she's not an Indian."
I have a hard time believing that the entire point was to temporarily bother people. I mean literally every president does this just by virtue of American partisanship.
I think the goal was a transformative presidency that cemented Trump as one of the best presidents. But he just didn't have the aptitude to pull that off.
There was no reason to believe that they would get what they wanted policy-wise from a Democrat or from a different Republican candidate. The next best thing is to make all of the bad people angry, which they did get.