I understand what you're saying. But, if we were to go off of what you are saying, we might as well include the Tooele area, all of Davis and Weber County, and heck, why not the Salt Flats? and everything that is not blocked off completely from mountains and such? Because if you had a telescope you should see Wendover from Salt Lake City because it is not interrupted by Mountains. It just does not make any sense.
The Salt Lake Valley just does not include Davis, Weber, or Tooele counties. It only includes Salt Lake County. It includes Salt Lake City, Magna, West Valley City, South Salt Lake, Murray, Sandy, Draper, Kearns, West Jordan, South Jordan, Herriman, and all those other unincorporated areas such as Holladay, Cottonwood Heights, Taylorsville, Bennion, etc.
http://en.wikipedia.org/wiki/Salt_Lake_Valley