It's an old thread. I haven't been paying much attention to it lately.
And the answer to your question is "yes", but it would have taken longer. On the plus side, it would have kept constitutional protections then in existence that were damaged by the aftermath of the war.
Slavery was evolving out of the culture. As the Northern States one by one gave it up, so too would the Southern states eventually, and for the same reason; Social pressure.
It was just more difficult for the Southern states because so much of their economic activity relied on it, whereas most of the economic activity in the North did not. Indeed, Slavery became seen as a competition to the labor market, and in the North was vehemently opposed on that basis too.
Thank you.