Sorry, but I have to call out that this narrative is not correct. It is not 'Trump versus Establishment'. That is painting a false picture that if you oppose Trump, you are establishment or helping them.
In reality it is Populism versus Establishment versus Conservatives.
Trump has latched on to the Populism crowd first. Many Conservatives joined him for various reasons.
However, many more Conservatives (as shown in the election results) have voted against Trump (over half the votes or more were for another candidate other than Trump).
The number of actual 'establishment' wouldn't fill a small town phone book's plumbing section.
It is an insult to the tens of thousands of actual Conservatives to say they are siding with the Establishment just because they don't support the Populism of the day.