What about linear agriculture that depends up chemical fertilizers bought in? Those chemicals then run off and enter the water table. Who pays to clean up the water at the sewage works and water treatment plants?
Circular agriculture uses animal and plant waste from the farm to make organic fertiliser. Very little escapes the loop except for agricultural products.
Circular agriculture may seem less profitable than linear agriculture. But if the costs of clean up are brought into the picture, then it’s harder to make a case for linear agriculture that degrades soil and reduces biodiversity. I can speak from my own experience of seeing fields where the soil had dropped 30cm or more compared to the surrounding land because the structure of the soil had been destroyed. In the longer term that only way that linear agriculture can keep going is to bring in more and more chemical fertilisers to make up for lost nutrients.