The problem (and I refer to it in my sig) is that the ends of the spectrum are controlled, as you infer, by a relatively small amount of very LOUD people, leaving the rest of us (the majority) wishing they'd find another damn hobby so that we could get to work on improving things.
.
You are correct that the political extremists control their parties, but look at the results of the election: Hillary couldn't force Democrats to leave their homes and they chose to stay home. Trump voters were voting against the Republican mainstream. Many of Trump's voters were former Democrats; specifically white blue-collar males. The very group both parties have trampled upon.
If Trump doesn't produce, these same American voters could flip Congress at the midterms or all in 2020.
I can almost promise you that if Trump does not find a way to deliver, and by deliver I mean for everyone that is a legal citizen in the country, He will be gone after the first term.
I know its hard for some on the left to understand but, there is a growing group in this country that want to see true equality, we want blacks to do as well as any other group, same with LEGAL hispanics. What we are looking for, and by we I mean myself and those I speak with directly in person since I cant speak for someone I dont know, are jobs, a strong economy that allows everyone that participates to have a chance at reaching their goals, the debt begin to decrease instead of constantly increasing and border security and control.
Give us that and he could see a second term, Give us that and I think that many on the left will help him into a second term.
Its time to get rid of all the animosity between self defined groups in this country.