Yeah, the oxcart delivery system would be inefficient.
The complete lack of free will is indeed the point. The explanation isn't really an explanation, even in theology, it's a way to avoid responsibility and avoid examination.
Had the line of technology followed the same path upwards that it did from the late 1700’s to the mid 20th Century, they would also have had aircraft, steamships and other motor vehicles, somewhere around the time of the Vikings................