Have you ever worked in a field?
I don't know if you ever actually worked on a farm for any length of time, but it's hardly a romantic, blissful time. It's a lot of hard, back-breaking work from sunup to sundown. When you get done for the day, you don't have the time or energy to surf the internet, read a book, watch a movie, or visit with friends.
"Sustainable" agriculture means subsistence agriculture, where each family barely produces enough for its needs. Even modern organic farms use a lot of mechanization to plow and till the fields, harvest, and so on. That still means a *lot* of petroleum -- nobody knows how to do it with windmills and batteries.
