>> Fertility isn't "free". You pull nutrients out of the soil whenever you harvest.
> Simply not true. Many plants accumulate surplus nutrients in their root systems or provide the required support for the soil live that sequesters nutrients in the soil. All of that remains in the soil when you harvest the plant,
That's inaccurate and simplistic.
_Some_ plants generate _some_ nutrients in the soil. The most common example being legumes (in symbiosis with bacteria) fixing atmospheric nitrogen into a form essential for plant life.
However all plants have complex nutrient needs. So even those that contribute something to the soil will remove other nutrients.
In the example of legumes, to simplify, if the whole plant is harvested, they will have made a net contribution of nitrogen, but the soil will still be depleted of e.g. Phosphorous and Potassium.
> if you are not dump enough to destroy the soil live by tilling, which sadly is currently the norm in industrialized agriculture.
It's not a dumb approach, it can make sense. And it does not "destroy" the soil. Yes it _can_ cause leeching, soil erosion and depletion of some nutrients, but all these ill effects can be dramatically lessened by good practice.
In Europe we have soils that have been tilled intermittently for millenia and are still productive.