As a species we finally got rid of it (at least officially) in 1981 when Mauritania became the last nation to outlaw slavery.
Slavery has not been eliminated. And will never be eliminated. Because it is natural. Laws outlawing what is natural, never work. Anti-usury laws didn't work either.
Man thinks he is more powerful than he really is.
There are damned facts that we perhaps wish were not true, but I don't see how it will help me by lying to myself, just because those realities are uncomfortable.
The institution where physical ownership of another human being was acknowledged as acceptable by society and ones "property rights" were enforced by the state is gone.
True change must happen from the bottom-up. It was not laws against slavery that ended slavery but moral outrage.
Man has the potential for infinite self improvement. However, we often seek out easy and false fixes to challenges because the true solution is too hard or too inconvenient.