Ah, the master of bad takes is at it again.
> Slavery had basically been a thing for all of human history up to that point,
Except that of course it wasn't.
> and based on my discussions on HN many smart people don't believe a lot of what Adam Smith said.
And many smart people do.
> There are still a lot of basic economic ideas that would make people much wealthier that struggle to get out into the wild.
Yes, such as the one that wealth is not very good as a context free metric for societal success.
> With that perspective the near-total abolition of slavery in a century seems pretty quick.
You missed that bit about the war. If not for that who knows where we'd be today.
> And we see what happened to the people who tried to maintain slavery over that century - they ended up poor then economically, socially and historically humiliated.
Yes, they relied on the misery of others to drive their former wealth, but they are not the important people in that story. The important people are the ones that were no longer slaves.
And never mind that many of those former slave owners did just fine economically afterwards, after all, they already were fantastically wealthy so they just switched 'business models' and still made money hand over fist.