[deepsun]

You're moving the goalpost from "prevent starving" to "fully self-sustaining".

You don't need 99% variety of cuisine in case of a big war, you need calories. A lot of calories.

UPDATE: and BTW, if world population is growing (no global starvation), then it's clearly self-sustaining, no? So some countries must be self-sustaining just by math. At least one country must produce more than it consumes, otherwise, if everyone produced less, then we would have global starvation.