You're making a lot of assumptions, and they aren't founded. Of all the people I've met who have gardens, the vast majority of them do some form of composting.

You're making a lot of assumptions, and they aren't founded. Of all the people I've met who have gardens, the vast majority of them do some form of composting. Tilling is almost never used as is is too labor intensive, they mulch instead. They plant a diversity of crops, and not just annuals - a plethora of perennials as well. They typically don't spray pesticides, though some will spray soapy water around pests. Most counter pests by creating habitat for birds and beneficial insects like lacewings, and by intermixing pesticidal plants into the garden. This sort of gardening absolutely decimates conventional ag in terms of food/acre. It is also sustainable, produces better food and creates an attractive green space. Properly performed, permaculture farming principles can even reclaim deserts. The cost is labor, but what if all the people trying to sell you stupid shit you don't need decided to farm instead? Can you imagine beautiful green cities with fruit trees and gardens everywhere? How nice would it be to be able to forage in your neighborhood to get fresh vegetables for dinner rather than go to the store? That can be reality, if we as a species can overcome this idea that we need to produce and collect as many widgets as possible.