Where is your source material that they did it out of greed?? Most things I have read was that they did not know what to do with them because of the fear the horde would rise up again and pose a threat and this was a more nobel thing to do than slaughter them (Like what the horde victory outcome would have been).
Sure, people like Blackmoore took advantage of this situation to profit off of it and use it for his own ambitions. You see this outcome in Thrall: Twlight of the Aspects when thrall visits the Alternate timeline when he died as a baby and Blackmoore rebeled aganist Lordaeron.
But it was not the intention of the state to profit off of this if anything it made the kingdoms go bankrupt because how expensive it was to maintain.