...The main thing to realize is that the destructive foolishness they're selling is a fairly popular political position in the US electorate, and while it's not a majority position, it's most popular among the demographics with the highest propensity to vote.

You can't get rid of that just with some kind of structural reform, as long as the government is more or less democratic. Mandatory voting might help a bit, as would reducing the number of veto points held by an intensely committed minority. But they don't just go away.