How long could slavery in the South have persisted without the war or a different outcome?

[NewYorkExpress]

Slavery would still be legal in the South. That said, the South probably wouldn't have opposed things like the Civil Rights Act if passed in the 1960's or 1970's in this universe, necessarily. as they would have instead sought a carve-out to protect slavery (maybe granting Slaves the right to vote, etc. in exchange for maintaining the existence of slavery.).

In the present day, slavery likely would be very rare, and restricted to the uber-wealthy (and possibly multinational corporations operating in southern states), but about 99% of southerners do not own a slave, or interact with one in their daily lives, and there are actually more free persons of color in the South than there are slaves, thanks to new laws, that specifically restrict slavery to persons convicted of a serious crime (essentially replacing either the death penalty or life without parole sentences) in most southern states. These laws were largely passed because of the White population's inability to acquire slaves around the time of the Great Depression.