Well, the "Lincoln GOP" was also generally in favor of tearing down and burning confederate flags, so I think it makes more sense to compare things over a shorter time-periods like "in living memory."

Parent poster's explicit "two decades back" scale is entirely reasonable for the phenomenon they are pointing out.

Lincoln was concerned about national unity foremost, and allowing the south to preserve its identity facilitated that after the war. It may have been the most successful reconciliation after a bitter civil war ever in history. Regardless, the economic forces shaping the nation have been shifting around but ever present since the founding. We were fighting about a central bank in 1789 and are still fighting about it today!