I can't disagree with this analysis. It's a long process to impeach a president and it is impressive that his base is so loyal. The good thing for America is that Trump has not affected the economy because big business really doesn't care anymore and despite Trump's threats. 
Trump will propbably survive 4 years because it's too difficult to replace him. It's up to the Democratic Party to find a better candidate that doesn't resemble Clinton. 
I still think Trump will quit if Meuller requests his tax returns. Trump is all about winning and saving face and enriching himself and his family.