Trump's election provides a counterexample to the claim that the opinions of voters count for nothing, otherwise we'd be looking at Hillary Clinton's second term or first after Mitt Romney.

Many of the promises Trump made were absurd, irrational and couldn't reasonably be delivered on, and Trump himself was the easiest candidate to read in recent American political history. Voters being unwilling to exercise their power judiciously isn't the same as them having no real power to exercise.