> but it is still recovering from
I.e. slavery did not benefit the Indian economy, nor the Kenyan economy, etc. Neither industrialized.
The US economy did industrialize (except for the slave states), and did not rely on slave labor from other countries, either, and it grew to economic dominance.
I know there's a theory that the northern economy depended on the southern slave economy, but when it was cut off from the southern economy in 1860, it prospered while the slave economy crashed.
The Confederacy crashed economically because they tried to pull a 19th century equivalent of the Arab Oil Embargo, cutting off their main export crop in the hopes of compelling Europe to intervene. The Confederacy suffered from what we'd call in modern times the resource curse--ironically, one enabled entirely by industrialization.
Right, obviously. The reason why Britain invaded is because they wanted India and Kenya to work for Britain. Slavery benefited Britain.