That is true.
A lot of people don't realize this, but the Southwest market for NASCAR is oversaturated- I think that hurts CA. Auto Club, Phoenix, and Las Vegas are all within 5 hours of each other. That's a big strain being outside of NASCAR's "core" area trying to support what is currently 5 points-paying races a year plus the Clash.
In my Fantasyworld, Phoenix would be scrapped (just because of its location). A new track would be build halfway between Salt Lake City and Denver (Grand Junction, CO probably). I think it'd be a HUGE hit as you'd have local fans as well as people vacationing with all the national parks in the area. Denver, Albuquerque, and SLC are all some of the fastest major cities in the US that have seen sustained double-digit growth in the last 20 years.