[toss1]

That may work when the global population is 200 million to maybe 800 million, and it didn't even work that well back then.

Feeding eight billion plus people requires scalable technologies.

So, which nine of every ten people should die? You volunteering?

Who owns the land on which to do this farming? Oh, perhaps start with one of the oligarchs, Bill Gates, who owns 275,000 acres, ostensibly to increase agricultural prodictivity, but still, it's his land not yours or mine, so how will we buy the food from him without a means of earning money?

My family gardens, but with a LOT of work, we produce only enough to supplement diet for part of the year. Fully sustaining would require multiples of the land we have...

Also, look into the actual lifestyle of subsistence farming, even for those who DO own the land. It is generally miserable hard labor and still entirely unreliable. One crop failure and your family gets to starve for a year...