Where do you think the plants' nutrients come from in those growing methods? Petrochemical plants also set to run out of resources. You're adorable.
Look at permaculture food forests and how they rebuild topsoil. While we still can.
Look at permaculture food forests and how they rebuild topsoil. While we still can.
Petrochemical sources.
Which, you might also worry about running out of, in about as short order as topsoil.
There was another commenter here with more expertise on actually growing things this way - they suggested that leafy greens were the only thing we could grow efficiently with this method. Which does have a certain air of "truthiness" to it.
To answer this question we should look inside ourselves