It may be true BYU did not bring more attendance to WCC schools but that is because they WCC schools have no support from their own students and alumni. They don't care about their sports programs. MW would get really excited if BYU came back to town. The Pitt would go crazy, USU and SDSU will pack their arenas. MW schools love to hate BYU and with them coming crawling back would fuel that fire.
WCC is so indifferent even if BYU was a top 10 team they would not come. I have been to the Pepperdine game past 4 years at Pepperdine. I don't think most of their students even know they have a bball team.