The story is more complicated by the fragile game setup by the primary system that amplifies the power of the extremes. Let's consider the game with the following simplifying assumptions: a) the prime directive of politicians is to remain in office, and b) the way that one wins elections is to mobilize one's supporters to vote and discourage one's opponents from voting. Given the rules of the game, politicians seeking office and serving in office must serve up the extremes to win, especially is highly gerrymandered elections. The bases that vote in primaries tend to a) have time on their hands, and b) passionate about cultural issues. No amount of education or persuasion will influence these votes, once they've made their committments.

Now consider the game chance if politicians knew that universal voter turnout was guaranteed. Under that game, there'd be no need to juice up support from the extremes. That won't make voters any better, but it would likely regress to the mean.

After enough cycles of that, with a different incentive structure in place, the same electorate with the same candidates would produce very different policy outcomes.

So it's not just the voters, it's the structure of the game.