A slave and a poor free man working equally hard look exactly the same, and differ only by consent. The difference is hard to tell for rich people, but poor people are
very clear on it.
I strongly disagree with your history telling!
Before industrialism, the whole world was poorer than the third world is today. Britain didn't get rich from plundering India or anywhere else, in part because there wasn't much to take. Every country was dirt poor by current standards.
In the last ~250 years industrialism and capitalism created wealth through inventions, industrialization and hard work. Now more than half the world is rich. China is already a medium income country, after having been desperately poor only 30 years ago. India isn't far behind.
Some pockets of real poverty remain, but the world will run out of poor people a few decades, unless trends take a serious turn for the worst. None of this depends on exploiting poor countries. Quite the opposite. The more advanced countries there are to trade with, the better off everyone is.