The author explicitly acknowledged that the deplorable majority can pull the lever once every four years, “At most, working-class voters can cast their ballots for an “un­acceptable” candidate, but they can exercise no influence on policy formation or agency personnel, much less on governance areas that have been transferred to technocratic bodies”

But once in office their guy maintains the status quo even though populist rhetoric got him into office.

So far this theory appears to be true. Historical data corroborates. What is less certain imho is that grassroots activism has ceased to be ineffective. Nobody expects the pitchforks and guillotines until they show up on their doorstep.