There were enslaved people that did exactly that. White enslavers feared poison almost as much as an uprising, because enslaved people prepared all their food. After Nat Turner’s rebellion was put to a violent end, the terror inflicted on the enslaved population is hard to overstate.
On top of potentially having never left the square mile or two of the plantation they were born on, dogs were used to hunt enslaved people who ran. Those who were recaptured were often physically mutilated to prevent further escape attempts. These acts were typically carried out in front of the other enslaved people. The cost was too high and the barriers too difficult to surmount for many people. Add to that, they may have had children or a spouse they might be forced to leave if they ran.
For some who were extremely clever (Henry Brown mailed himself to freedom) or who were able to make contacts with people who could hide them on the Underground Railroad, they were able to make it. But everyone who didn’t run was kept in place by a system of racial terror, not out of a lack of desire for freedom.
