From the article:

It is a strange paradox that a billionaire like Trump could pose successfully as the champion of the interests of the working class. He is, of course, a faithful representative of his class – the 1 percent of super-rich Americans who own and control the nation.

For a long time, the Democrats were able to pose as the political representatives of the working class. But decades of bitter experience has convinced millions of workers that this is a lie.

They are looking for a radical alternative. This might’ve been provided by Sanders, if he had decided to break with the Democrats and stand as an independent. But he capitulated to the establishment of the Democratic party, and that disillusioned his base.

This left the road open for a right-wing demagogue like Trump, who seized the opportunity with both hands. It is not generally known, but in 2015, Trump privately told Yale business school Professor Jeffrey Sonnenfeld that he purposefully copied the anti-corporate messaging that Bernie Sanders’ campaign had shown was effective.