It's always going to be more complicated than that. There's a TON of un-used ex-farmland in the US, and across the world, which fell out of use because prices

It's always going to be more complicated than that. There's a TON of un-used ex-farmland in the US, and across the world, which fell out of use because prices dropped too low (the entire eastern part of the US used to be farms, and has now reforested). So if food prices rise enough, we're going to start re-farming marginal lands. The world is never going to "run out of food", probably not even enough to affect most Americans / Europeans notably, but will result in hunger in the third world -- but it's not like that's a solved problem right now.