If you are not trying to force greater yield in order to squeeze out profit, the nut trees can do well to yield enough for people to have their fair share.
When done as part of a practice that involves diversifying crops, the entire smallhold is far more resilient to any number of external pressure, including climate, pests, market crashes, etc.
Too bad resilience against future problems loses to maximizing profits, so all the resources are capital-efficiently extracted from one location before moving on. Even if I buy local, it’s likely that it’s farmed at a damaging scale. I’m guessing that sustainable farming, crop rotations, etc have fewer externalities.
(x) doubt
If they actually can pay for "very expensive water" i.e. water at the rates that residential/commercial users pay, then fair play to them. But from what I heard, they are only profitable by paying near-zero (orders of magnitudes less than other users).
The issue isn't the cost of water, it's that "free" water drives everything else (or imported water - the United States major export often seems to be exporting it's water in the form of crops, food, etc...)
After Covid and all the disruption of international trade, self-sufficiency in food production will be considered more important than before.
Water is heavily subsidized in AZ. There is little incentive to conserve it.
And farming has been booming in Arizona. I lived there about 10 years ago and even then there were a lot of complaints about all the tree farms (almonds, etc.) that were showing up in Arizona. Massive water consumption and virtually impossible to be sustainable in the desert.