Pat,
Don't be silly, I know you know your GCA but did you think before you typed exactly WHY the desert gets little or no rainfall? (Back to my explanation; water, mountains, rain etc.) Are you trying to argue that it is untrue that water evaporation from the deserts goes to someplace other than to the east?
I am sure if you confer with your board of sand experts they would also agree that the Colorado River is under a lot of stress from expansion.
I have not played any Las Vegas courses because I am not really a Las Vegas fan in general. I have played many other desert courses from Palm desert to Arizona. My question would be is water the only type of hazard that can create an heroic carry?
Oh yeah, ranching and water tanks. I probably would have just made that up if it were not true.