> Why do you think the slave-free north was much richer than the south, before the civil war?
Because the North had a diversified, industrialized economy, while the South specialized in cotton production.
But the North never could have diversified in this way if it weren't for the South. First because slave-grown cotton was a major source of capital for the overall US economy - it provided over half of all US export earnings. Second, because the demand for textile factories, meat processing plants, insurance, shippers etc. in the over-specialized South is precisely what created a market for the North to diversify into.
This is on top of the fact that the North itself had slaves for a long time, from initial settlement to abolition many decades later.
Because the North had a diversified, industrialized economy, while the South specialized in cotton production.
But the North never could have diversified in this way if it weren't for the South. First because slave-grown cotton was a major source of capital for the overall US economy - it provided over half of all US export earnings. Second, because the demand for textile factories, meat processing plants, insurance, shippers etc. in the over-specialized South is precisely what created a market for the North to diversify into.
This is on top of the fact that the North itself had slaves for a long time, from initial settlement to abolition many decades later.