Why slavery persists?

Many a study I went through. The argument everywhere is focused on the desire for quick wealth, scant regard for law, the fall in moral standards, and a few more of this ilk. And, the bulk of attention falls on the slave trader. I think one important issue is being forgotten. People chose to become slaves, whether willingly or otherwise, since they already would have been in a condition worse than slavery. Or, they found slavery, a lesser evil. If we concentrate here, slavery also will make a fast exit.