Soil fertility is similar to irrigation. As fertility decreases, it can be compensated (to a point) by fertilizer, but at an increased cost. As the aquifers are pumped faster than they are replenished, water can be pumped from deeper depths, but also at an increased cost. Both impact the economics of farming. And for many communities where agriculture is the economic foundation, decades of non-sustainable practices have created economic headwinds.
Things can certainly get worse. However, I don't see cheaper water or less fertilizer changing the economic outlook. Even with a slight increase in profit, you still have things like health insurance that are ever increasing, and the top line is too low to begin with.
https://en.wikipedia.org/wiki/Ogallala_Aquifer (primary aquifer in the midwest)
https://en.wikipedia.org/wiki/Optima_Lake (lake never filled due to decrease in aquifer depth)