We have lots of agricultural land; too much, actually. This is a side effect of the green revolution.

What we in California don’t have is sustainably plentiful water, or a sane system of water rights to apportion it.

In SoCal, yes, but things are (mostly) fine in the north and in the central valley.

More frustrating is all the water waste due to "use it or lose it" type policies around commercial and agricultural water allocations.

A trip to Palm Springs is an eye-opener. You see so many sidewalks being watered at all hours of the day, and the water just flowing right into the drains. Such a shame in a desert area.

In much of the US, water is a common good and there are no water rights.

There is no sane system of water rights which is why there are cotton fields in Arizona.

Out west, water rights are based in common law, sometimes formalized by legislation. And common law is based on how miners and prospectors resolved water conflicts while panning for gold.

While there may be no sane system, the legacy of "first come, first serve" and ",use it or lose it" is particularly insane.