What would be the point replacing Trump with someone whose policies and history are nearly indistinguishable from those of other Republicans?

Exactly. This is one of the main reasons Clinton lost. Why get off the couch and vote for the Democrat racist, lying, corrupt war-monger who says the US is already great? The differences between Clinton and Trump were in degrees, not in basic substance.

Biden v. Trump would be the same. Another nail-biter. If Biden wins, he’s already said his goal is to take the US back to exactly the situation that gave us Trump. Not exactly inspiring rhetoric for the 80% of Americans living paycheck to paycheck.