I personally don't believe that the ethos of Trumpism will survive past Trump's term in office, be it 4 years or 8, unless a similarly iconoclastic maverick rises up to take the reigns, and Trump is too rare a phenomenon to be replicated that quickly.
I had similar feelings regarding Trump early on, but then read a book by Pat Buchanan that cleared things up for me. Trump represents traditional republicanism or what detractors call paleo-conservatism. I wrote about it here before the election: Understanding Trump
I think Trumpism or the Trumpion Revolution has legs, and he will transform politics, including in particular the neo-con Republican Party, for decades to come.
I note that Newt Gingrich has a book coming out this summer with the same title, "Understanding Trump".