One possible scenario is that Idaho and NMST get an invite to the Sun Belt for football only, and join with Denver, Seattle, Boise, Utah Valley, and Bakersfield to form a new non-football WAC. The Sun Belt would then get to 12 in football, and nobody really wants any of these schools for the other sports without football.
A less likely scenario would be the WAC ceasing to exist, Idaho moving to the Big Sky, NMST moving to the Sun Belt, Denver and Seattle moving to the WCC, and Boise moving to the Big West.