There is enough water in the Southwest for a sizable population, of course. The problem ahead is how to distribute a constrained resource to that population without deferring to lobbied interests, wealthy landowners, golf-course owners, etc. That's an uphill battle, to say the least.
The U.S. went all-in on globalization. That includes globalization of food production. For 50 years the typical USian has taken bananas and coconut for granted. Coffee is a staple in every kitchen.
Produce and dairy of countless varieties are produced in California for consumers around the country and indeed around the world.
Would you argue that globalization of the food supply chain is a mistake? Do you propose that Chicago grow its own spinach? Should Saudi Arabia grow its own alfalfa? Should apples and grapes consumed in Oklahoma be grown in Oklahoma?
I suppose many people are rethinking this whole globalization strategy. From microchips to mozzarella. Economics: the spectator sport with real spectator consequences.
https://grainger.tennessee.edu/grainger-county-farmers-page/
Literally famous for tomatoes, man.
https://farmflavor.com/tennessee/tennessee-crops-livestock/w...
That said, all 70 growers combined total less than 500 acres. It's a good start.
But it doesn't prove that California "desert" is the worst place to grow produce. What is the total yield of those 500 acres? What is the price per pound? How well do they compete in the market?
Again, I hope they compete well. But I know that the tomato in my back yard cost me 5x the one coming off the truck at the local grocer.
"Globalization" would include an elimination of domestic agricultural subsidies and tariffs such that everyone is on a level playing field, which is something we have not done in our agricultural sector.