Hmmm... I grew up in Iowa and the "old" farmers I knew used GPS units that measured fertilizer distribution to the square foot so they could compare it to yield in that square foot and adjust the flow on that micro level next spray to even out yield.
I don't think farming is what you think it is these days.
Its not the same at all, do a search for "farming robots" on Google. Factor in the age of a lot of US farmers, and price of farmland, and things really start looking like they are about to undergo a significant change.
A nearly complete takeover by automated machines is already underway with farming. Robots coupled with software are really how software will eat the world..
The reason capitalism works so efficiently is it forces change. The "old boys" may have monopolies today but they won't have those same monopolies tomorrow. Its happening everywhere. So many opportunities.
I don't think farming is what you think it is these days.