I've heard the most prosperous times for the US are when the president's party is different from the congressional majority. Few laws get passed, so things stay stable for businesses.
No, the issue is half of Americans and American states are still into Red-state zero-sum policies which don't work very well in a modern world and modern economy. Today you want the black/female/trans/foreigner working at their absolute full potential, not slaving in your farm.
In the past it didn't matter so much economically because slaving in your farm was still one of the most important jobs. In 1900, ~40% of the American workforce was employed in agriculture. Yet even then the (ex) slave states were poor compared to northern states because they didn’t know how to invest in their population (still don’t).
