How did you come to this conclusion? I'm close the industry, and in my experience, corporate farms spend a great deal of effort maintaining soil, which includes using drones to visually inspect crops to see where soil may be lacking certain nutrients based on foliage color analysis.
I believe prime tillable land in Iowa currently goes for something like $10k/acre. That's not really in the realm of "cheap" when you need 100s of acres to be profitable in today's farm economy.
Further, the agricultural colleges in the Midwest have extension offices specifically devoted to spreading best practices regarding sustainability and soil health.
Healthy soil is productive soil. There's a reason yields keep going up, and its not just down to plant breeding.