That's a moot point for as long as we still have 3.5 billion people engaged in subsistence level farming. All of them need to be brought into the modern economy

That's a moot point for as long as we still have 3.5 billion people engaged in subsistence level farming. All of them need to be brought into the modern economy, and taught a specialty. In other words, if 50% of the human race is still wasting its time with farming practices that have barely changed since the Neolithic, then there are still a lot of ways to grow the economy, even if the population is falling.