This video from the movie, "The Yes Men", along with the planet Illium in Mass Effect 2 (with indentured servants) puts this question in my mind:
As you can see laid out in the video, if someone is a slave owner, they have to provide health care, food, clothing and shelter for their slave, or their "investment" would go to waste. Done in a developed nation it can be costly. Well, as observed by the American economy, and the push for "right to work" and increasing on-demand temporary labor, and no guarantees of individuals even remotely ever making enough money to provide things like healthcare or shelter (there are homeless people who do work as day laborers), the market seems to have optimized itself to do what customers need, without people having things that even a slave would have. So, the question here is: Is slavery no longer an economically viable option? The Yes Men video indicates, AT LEAST, it isn't economically viable to have slaves in developed nations. Just curious if planet Illium, for example, would end up having indentured servants on it.
By the way, I would suggest anyone who doesn't know what the Yes Men are about, to go do a bit of research on them, if what you see there generates strong opinions of them.
