Desalinization is not cheap. THere would be enough water if the state governments were corrupt pieces of ****.
I think the prices have come down a lot. Most charteboats here in the keys have a combination ice machine/fresh water made with saltwater through a desalt process and they cost about a grand.
On a large commercial process and selling water at low rates as a huge pipeline crosses the state its probably doable.
My guess is the state probably throws away enough money on silly things like sanctuary cities that they could easily come up with the money if they really cared about the fish and the game and farming.