Maybe it's not just about the votes?
Maybe what we're observing, with left-wing capture of most institutions despite roughly half the country voting Republican, is the limits of focusing on just capturing enough votes to narrowly win elections, as per conventional political theory. Maybe a party has to also win hearts and minds of a significant enough fraction of elites if not even wider professional class to be a viable force in society. Else you can't be effective even if you're in office - or rather, as with Trump, end up implementing largely your party's professional/elite voters view rather than majority of voters' (eg, no wall but corp tax cuts). More fundamentally, legislation wouldn't fly if it doesn't have legs - it only works well if it caps and reinforces changes already underway in the society - meaning, already being widely spread and promoted by a non-trivial fraction of elite and professionals. And if all legs are turning left not much can be saved by legislating the right turn.