If they could have made more money share cropping then developing the plantations system, why didn’t they do that in 1800 instead of the late 1860s.
You’re suggesting a plantation owner should enter into a sharecropping agreement with someone with zero skill set. Someone who had never seen a cotton plant or plow in their life. Nonsense.
Sharecropping would have been an alternative to slavery AFTER the workforce had acquired the skillsets.