Those mega farms are contracted by major corporations with fixed prices for the crop. Maybe I am wrong. Please correct me if I am.
That’s not really the point, the point is the machinery on private farms of 80 quarters cannot ever be replaced by oxen. Take a tour of a naverage multi thousand acre family farm in the midwest and you will understand how impossible the idea is. The day the world goes back to oxen to farm will be the day billions of people will be starving to death.
When enough people die farming with oxen will be practical again.