I don’t know SLC very well but I’d guess it’s a combination of water consumption, and a bad value:land ratio because the wine won’t be good.

I don't think there are good or bad wine growing regions as much as there are places where people have figured out how to make good wines. The Finger Lakes had a bad reputation once but people figured out Rieslings and some more affordable whites that reputation changed. More recently it was famous for soda-pop sweet wines like Red Cat but I've had some dry reds lately that weren't as bad as what I had 20 years ago.

People are making progress in Utah too

https://en.wikipedia.org/wiki/Utah_wine

It was a rhetorical question.