In historically authoritarian countries, people sometimes vote for populists promising the return of the glorious past (never mind that past being a totalitarian nightmare). The US has been a democracy since day one. Moreover, Americans not always reward competence but are usually quick to reject any utter incompetence.
So, what gives? What is this "great again" thing that makes tens of millions vote for their own suffering? It might've been a novelty in 2015, but it's 10 years later now.