This has nothing to do with capitalism as communally (or otherwise non-capitalistically) owned food production entities would also be highly incentivized to gro

This has nothing to do with capitalism as communally (or otherwise non-capitalistically) owned food production entities would also be highly incentivized to grow crops in the desert because it just works better, assuming adequate water supply from pipelines or rivers. This is observably true as many countries are using desert/dry land areas to grow crops more efficiently, including those more on the "socialized" spectrum of mixed economies. The thing we should do in this situation is increase our ocean desalination efforts (not to an extent that would counteract sea level rise, but it wouldn't hurt), alongside creating more water pipelines to achieve better distribution into areas which need it. We aren't going to stop crowing crops in desert conditions. It's too effective. We should build more water pipelines to bring water into regions like the California central valley and Colorado and Utah where water is more scarce but crop conditions are good aside from the water availability.