Well, there is a smidgen more of a backstory to it. Both Will Bonsall and John Jeavons have written pretty good gardening books that explain their thinking in regards to worms and bird and deer poo.
Also in regards to 75% claim in article I linked, references are hyperlinked. Leads back here to a scientific paper here:
http://josephpoore.com/Science%20360%206392%20987%20-%20Accepted%20Manuscript.pdf I think the middle ground between Veganic for everyone vs
producing 60% more food by 2050 might just be eating less feedlot fed cows and cow milk and factory farmed chicken, eggs, and pork. Growing corn to feed cows, pigs, chickens, and gas tanks might not be the best use of soils.
One thought on bad soil. I would rate my own eight acre parcel as perhaps not suitable for vegetable growing. Its got 7 inches of topsoil over 7 inches of clay accumulation, over lake bed sediments. It was formerly used for beef production, irrigation was once attempted. The flatter porion was plowed and replanted with aggressive non-native grasses.
However, I could add 6 inches of sand to two acres of it for about $20,000 so assuming I had enough money to spend $20,000 on a car and chose to buy sand instead I could greatly change my soil structure and soil depth instead. Of course if everyone wanted to spend that kind of money on their soil we wouldn't have enough sand at that price. However, there are multiple ways to solve a problem, another might be growing a carbon crop and burning it to make charcoal. Then double digging and incorporating the char into the clay accumulation layer of the soil profile. Doubt I will do this, at least not quickly, but I would rather have better soil than a newish car.
Likewise it's pretty silly to destroy productive soils for buildings.