According to the thread below, half the country is the worst place to farm in the US, and I'm certain every other country in the world has the same areas( I sometimes suspect I am in one of them).  
So if by improving technology, weather, efficiency, or reduced consumption, production should exceed demand for the foreseeable future, and prices drive high cost producers out of business, What regions of the world will be the first and the last to become uneconomical to grow crops?  Land and rent prices aside, as obviously they eventually would change to reflect the profitability or lack thereof.

Not saying that this will happen, just speculating on what the implications would be.  

Or looked at another way, what regions of the world will be even capable of growing crops for the long term.  Where are rates of topsoil loss low enough, water supplies sustainable enough, and climate stable enough?  To say nothing of geopolitics or land loss to development.  

As for my little corner of the world.  In any scenario except global cooling, I believe that we would be competitive.

EDIT TO ADD:

Perhaps I worded that wrong.  I am asking about a scenario where worldwide demand can be met by (for example) half as many acres as we use today.  Obviously we can't all keep producing as much as before, economics will force all but the lowest cost producers out.  

My thoughts (and please feel free to refute me)  would be that anyone with these additional costs would eventually be pushed out:
-Irrigation
-climate conductive to pests that are expensive to control
-not getting a crop every year due to factors such as drought, or drowning, perhaps hail
-having to burn additional fuel/energy to control wind or water erosion or manage excess water
-chasing lots of acres for lower yields

Who would be left?


I know it sounds improbable, but history is full of industries who have gone through exactly this scenario, and only a few have survived.  The world may decide to quit eating meat( there is a trend already) We may have a quantum leap in genetics or production methods, or weather control.  Population may peak, or disease may decimate populations.