Scrat. You asked:
What would you have the government tell all the competitors to these farms who were not going to be getting tax dollars with which to pay their workers?
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I'd tell them a horrible mistake had been made re: slavery. That because the gov initially allowed it, citizens based their livelihood on it and made heavy investments toward it--and now that the gov was declaring it illegal, it was only right to assist both the slaves and the citizens that had invested their livelihood into the use of slaves, as the plantations reorganized their operations to meet new legal standards. The farms not using slave labor wouldn't be negatively affected by Emancipation, and therefore would have no need of assistance due to the new law.
I think the greatest benefit would have been to Freedman's assimilation.
If HG Wells had only finished that time travel machine...