A couple of things:

1) you're taking my comment too seriously.

2) assuming I had enough space to subsistence farm for my household (I don't), I wouldn't try growing lettuce year-round. Lettuce in the cooler months, peppers and tomatoes in the warmer months.

3) the majority of the lettuce I've prepared in my home this year did come from my patio

Containers. When it's nice out, they live outside. When it's not nice out, they move indoors. yeah yeah, not op, but it's possible. If you're growing food to sustain yourself for a whole year, I'm assuming you're willing to sacrifice some indoor space to accommodate.

Also, the GP doesn't read to me the way you're interpreting it. To me the GP has grown produce and purchased produce this year. The purchase hit him while the grown at home did not.