We're producing enough grains to turn everyone obese, at the current pace. The problem of famine is not one of Malthusian underproduction but bad distribution. The EU was destroying food in the 90's. We're using grain to feed huge amounts of cattle. The market distributes, and when the bottom sixth of the population has less buying power as the top thousandth, the distribution is going to be very unequal.

Un roi sans divertissement est un homme plein de misères

I didn't talk about subsistence farming. Please read what I said.

The "trend" to the cities happens because peasant farmers cannot make a living on the land, for reasons I outline above. The trend needs to be reversed by making it possible to live from farming. Why do you accept it as seemingly inevitable, as something that is just "happening"?

You have no strong opinion, you say, but your own ideas appear to be based on an a priori belief that widescale industrial farming must be the only way to feed the world. But widescale industrial farming in poorer or developing countries lends itself to colonial exploitation by large corporations in a free-trade environment, which in turn means plantation-type monocultures that are agronomically fragile and environmentally unsustainable. The counter-project is to support and empower smaller-scale farming carried out by those who (still) have practical knowledge of local conditions. There are immense gains in yields to be made simply by the use of existing well-adapted varieties along with better farming practice in an environment in which farming pays the farmer (not currently the case in the countries we are discussing).

See also this Open Thread discussion.