This only true in places that aren't environmentally supportive of agriculture. My family never had to buy vegetables. Granted we had about 2 acres of farmable land. We didn't sell produce, we harvested and froze until we needed it

Edit: Initial start up is definitely not as cost effective as buying from the grocery, but once you're able to harvest your own seeds, it's not that expensive to sustain your production

Where's that 4chan post where all the BLM rioters tried to set up a new community in Seattle or something. Then they had everyone give there skills and what that want to do in the new world, everyone was saying they can grow food. Then there was the crappest plot of veggies I have ever seen.