Farm workers went from 14m to 3m because farms became much more productive (even more than 14/3, since we produce more agricultural goods too). Surely you see

Farm workers went from 14m to 3m because farms became much more productive (even more than 14/3, since we produce more agricultural goods too). Surely you see that having fewer workers because the work is being done someplace far away is not equivalent having fewer workers because we can do more work with fewer.