Indentured servants weren’t chattel. Even if they were indentured for life as punishment for crime.
For one thing, their children were born free.
If I am not mistaken, the agreement that ended new slaves being brought in was part of the attempt to stave off the coming war. When did that begin?
At any rate, because of the Bloodiest war in American history,the south was ruined, the powerful benefitted. It was lunacy on the scale of what we have today.