Eh, the further left portion of the electorate has much lower turnout that the further right, largely due to apathy toward the centrism of Democrats. I think you’re right that a Democrat/Progressive landscape would result in both moving right, but I think the Progressive would be firmly to the left of the modern Democrats, and the Democrat would be firmly to the left of the modern Republican.
Eh, the further left portion of the electorate has much lower turnout that the further right, largely due to apathy toward the centrism of Democrats. I think you’re right that a Democrat/Progressive landscape would result in both moving right, but I think the Progressive would be firmly to the left of the modern Democrats, and the Democrat would be firmly to the left of the modern Republican.