And if between them the governments and corps own all the arable land and control them even more tightly than the cities, because they're the only luxury food, and goodness knows Arasaka isn't going to eat vat grown yeast/algae kibble that goes to feed the 10,000M+ of us who are mostly crammed into cities...
I don't know about anywhere else, but here in the UK we import about 40% of our food - and whilest we do export food as well, if we chopped that off, we'd still have a deficit of around 30%. If we tightened our belts none of us would starve, we overeat as a nation anyway. However, add approx 33% to our population (estimated global growth, UK would probably only grow by 10-12% but it ruins my rant
) and things start to become very tricky indeed. Price of food goes up, price of land to grow food on goes up - you're gon'a need money choomba, and where's the money? It's in the cities. But you'll have to be faster, leaner, meaner to get it, 'cause competition's vast and cunning.