Below are a list of reasons why the tournament has to stay in Las Vegas.
1. There are only 2 destination cities in the conference area at the end of Winter: Las Vegas and San Diego. The San Diego arena does not allow alcohol sales because it is on campus. The Thomas & Mack is an off-campus facility and thus allows alcohol sales. Let's remember that the conference tournaments are to make the leagues money, not to crown a champion.
2. The MWC tried it in Denver. No fans came.
3. The WAC tried it in Salt Lake City. No fans came. (Beginning to see a pattern?)
4. The WAC tried alternating sites for the tournament, not based on which team won the conference, it was just determined at the beginning of the year. Again, hard to get fans to go to Laramie, Provo, Fort Collins, Colorado Springs, Albuquerque, etc. Also, those cities would have a problem holding the fans if they came (hotels, restaurants, etc).
5. UNLV winning the tournament is actually pretty new. They didn't win it regularly when it was there before in both the MWC and WAC (I guess part of the time they were on probation, but still).
6. The coaches wanted it back in Vegas after 3 years in Denver. They must like something about Vegas.
Sure, there are a ton of reasons that the tournament could be held somewhere else, but quite frankly Vegas is the best spot for what the conference needs the tournament for: to increase cash flow.