The “lawns in the desert” thing never made a lot of sense. If we didn’t get enough rainfall to keep up the grass more-or-less, we’d have desert landscaping, too.
Of course, government buildings will still have lawns, and they’ll water them even when the little people can’t flush their toilets ... and we can sneak out and shower in the sprinklers!
The lawns and golf courses were all here (in most areas) before the CAP began taking water out of Lake Mead and other parts of the Colorado River.
Now of course, there is incentive for desert landscaping...the water company charges by the size of the meter before ever calculating water usage.