Liberius,
I think that there are a few things here we need to address or I feel that we will end up talking past one another.
-You are dealing in hypotheticals, an ideal situation in which the needs of all people are met within the context of a closed food system (ie Ireland will grow all it’s own food)
-My stance is that we are living in an age of intensive farming right now. Intensive farming whether it be hogs or strawberries (80% of America’s strawberries come from a small section of California) is extraordinarily extractive. Factory farming is the exact opposite of holistic.
-At no point in history has so much food been grown by so few people. on what is frankly so little land (as a percentage of total landmass versus what is actually produced).
-The reality is that the unsettling of rural areas and the treatment of food as just another commodity is extraordinarily damaging both to people and the earth.
-My approach is not based on making middle class tree huggers who are moving to the exburbs feel warm and fuzzy (this is what is happening to your freed up ex farm land btw). It is based on common sense and not thinking that I’m smarter than mother nature. It is also based on the belief that agriculture need not work against nature and that good husbandry techniques can help agriculture make a net return to the earth through healthy soil and environment.