Unfortunately, the trend shows Dems will turn more towards center before Reps but anything could happen. Reps went extreme right once Reagan was in office. Then Dems went extreme to counter that. Now, Reps have been forced to go to the extreme to counter the Dem's extremism. This is pretty much how it always works. One side goes to the extreme and the other side isn't smart enough to not play that game, so they go to the extreme and the other side goes more moderate.
But, in this situation, both parties have gone full extreme, which makes it harder to predict what will happen. If Dems don't start going more to center, I fear neither party ever will again until there is a major shakeup (war, famine, etc.) But, in the distant past of our country, this is when a new party was formed...Federalists decline, Whig defeat, etc. So, I see a new party eventually breaking through if Dems don't start trending center first. We all know Reps won't do it because they feed off of their greed and don't have a platform that centers very easily. With Dems being more conscious of social issues, it's much easier for them to do a 180.
One thing is for certain, if something doesn't happen soon, there will be no parties anymore.
"What's missing is the analytic rigor to try and paint a picture of what the economic impacts would be."
Now that's the type of critical thinking this country is sorely lacking. Unfortunately, what the economic impacts would be vary greatly depending on which party someone is so finding the truth isn't possible. And we all know compromising isn't possible either. Which leaves us with a broken system that will never be fixed.