It is about change in the ranks of elected Republicans. It is not about why Republicans are electing different representatives nor is it about why elected Republicans have withdrawn from office, except to assert without proof that it is Donald Trump's fault.
The article is certainly not about the issues that currently divide the Republican Party. The authors don't go there because to do so would take them into treacherous territory. That territory is treacherous because it exposes the essential fallacy of the piece. The Republican Party is riven to the extent it is because Trump's policies are an existential threat to the business model of the Republican Party. The evidence? The Republican Party has lost its financial leverage over Wall Street, having surrendered that to the Democrats while Trump champions the issues of the middle class.
In other words the customers of RNC INC have changed because of the policies forwarded by Trump and those Republicans in the business of being politicians rather than being statesmen have lost their sinecures. It is a pity that the fundamental truth expressed in the article through the quotation by Newt Gingrich was not explored. "There was only limited room for overt, aggressive anti-Trump Republicans. Not because of Trump but because of the voters. Trump doesn’t have to orchestrate the hostility people are running into.”
But Trump has made it morally impossible to sell out to those who sell out to China or, indeed, who sell out every day in every way. Trump changed the business model and the customers will not buy from the old Republican vendors.
Nicely stated.