As someone who moved to LA in the early 70s, and left LA in the late 80s, and spent some time to visit Palm Springs, Phoenix, and Las Vegas, I can say with full confidence that anyone with a lick of sense knew there was not enough water to sustain that growth that started back then, but that didn't stop anyone from building or buying those homes. They all knew it, but didn't care. It was, and still is, plain old stup…
This is clearly an area to think at a larger, national level like the thinking which led to the Hoover Dam and national highway systems. Anything less is shrinking away from the problem.