While the “institution” of slavery is abhorrent, not all slave owners mistreated their slaves. If you read the “Slave Narratives” in the Library of Congress you’ll find that many freed slaves did not want to leave the plantations. It was where many were born and raised and was the only constant they’d known. Their master’s family treated them well and many even said that they were “like family.”
I don’t believe that this justifies slavery at all but it does show that not all slaves were treated like Toby in Roots.
There are countless cases of former slaves sharecropping the former masters land to pay the taxes and to stop tax foreclosure. It was a group effort.