[SauronOfMordor]

I have no doubt slavery would have ended eventually, but I seriously doubt it would have been a result of pressure from imigrants.

Slavery was only economicly viable when land is essentially free. A slave would only work as hard as he had to. A free man working his own land would be much more productive, and could bid a higher price for land

[Froufrou]

"A free man working his own land would be much more productive, and could bid a higher price for land"

With what money? We're talking 40 acres and a mule here, that's it.