The US overproduces food to an absurd degree and isn't even remotely close to maximizing it's ability to grow it.

Anyway, Ag shifted production to the Southwest because when you don't pay the actual value of the water, it's great - lots of sun, long growing season, basically free water = cheapest production.

When water costs money....you'll see quite a bit of that production shift back up north.

One can import food from someplace with more water.

It's the same way we don't subsidize farmers to grow bananas in Alaska, and then pretend that bananas would disappear if we stopped the subsidies.