You are externalizing the factor of soil health. When we start a field with fertile, normal soil, and add extra inputs, yields absolutely go up in the near term. But after decades of that, then your yield is back to where it was when you didn't have inputs, and now your soil has become dirt. Yet the problem is you are required to pay for inputs just to keep that land at par with the year before. And if you want to wean off the inputs and switch back to the original method, yields will go down for a few years until the soil is regenerated. After which point you will still only be back to normal.
The increased yields from input-heavy factory farming can essentially be seen as a loan of yield from the future. If you are overleveraged, and your capital (in this case the nutrients in the soil) is finite then when capital is depleted (leeching into the environment in this case) getting back to square one will require investment or continued increase in leverage.
The increased yields from input-heavy factory farming can essentially be seen as a loan of yield from the future. If you are overleveraged, and your capital (in this case the nutrients in the soil) is finite then when capital is depleted (leeching into the environment in this case) getting back to square one will require investment or continued increase in leverage.