In the following graph, the rise in the price of farmland from the 1980s to 2010 does not seem quite as steep.
In the following graph, the price of farmland actually fell from 1980 to 2010.
In comparison with global farmland prices, farmland in the USA seems both much less expensive and not as subject to a rise in price.
Some of that talk might need to shift to the past tense.
There is the possibility that much of American farmland is in a long-term bubble.
This is because the ongoing and relatively rapid transformation of weather patterns will render some farmland much less usable.
https://www.newyorker.com/magazine/2013/11/11/climate-by-numbers
A typical rainfall map of the USA:
Here are some ways that this pattern has recently changed.
It is raining a lot more in the northeast, midwest and central states.
The southeast is getting less rain.
It is problematic to map this out a couple of generations into the future, but there has been at least one attempt.
https://www.pbs.org/wnet/peril-and-promise/2019/01/economics-climate-change/
Based on county-specific data from the Climate Impact Lab, economic loss due to climate change is concentrated around southern states where they should expect loss in agricultural yield and in high-risk labor as well as an increase in mortality rates.
It's happening now.
http://archive.is/on9Wh
One striking marker of expanding stress is the 100th meridian, a divide between water-rich and water-poor areas drawn nearly a century and a half ago by geologist and explorer John Wesley Powell. According to a team of scientists including those at Columbia University’s Lamont-Doherty Earth Observatory, the boundary—severing states from North Dakota to Texas—has shifted about 140 miles eastward since 1979 because of warmer temperatures or reduced rainfall. The scientists predict the West’s drier climate will continue to push eastward and pressure water supplies for farms and cities alike.
https://en.wikipedia.org/wiki/Vertical_farming
Vertical farming is the practice of growing crops in vertically stacked layers[1]. It often incorporates controlled-environment agriculture, which aims to optimize plant growth, and soilless farming techniques such as hydroponics, aquaponics, and aeroponics[1]. Some common choices of structures to house vertical farming systems include buildings, shipping containers, underground tunnels, and abandoned mine shafts.There are great challenges for vertical farming.
Vertical farming technologies face economic challenges with large start-up costs compared to traditional farms. In Victoria, Australia, a “hypothetical 10 level vertical farm” would cost over 850 times more per cubic meter of arable land than a traditional farm in rural Victoria [4]. Vertical farms also face large energy demands due to the use of supplementary light like LEDs. Moreover, if non-renewable energy is used to meet these energy demands, vertical farms could produce more pollution than traditional farms or greenhouses.
To extrapolate even further into a speculative future, a shift toward vertical farming would entail a significant shift in political and economic power toward urban areas which are already resurgent.
