What do Utah and Colorado add in terms of traveling fan base? I can't imagine more than a few hundred, maybe a thousand, show up at away games. What would BYU fanbase have added to games at the Rose Bowl or Coliseum, or either of the Arizonas? I would guess at least 0K. BYU fanbase would have traveled far better to P12 away games than either Colorado or Utah. But the P10 didn't want to hear about it.
Point being - it seems obvious that BYU brings a lot to the table in terms of competition, and attendance. Moreso than other potential additions. But if B12 is determined to go East for media market purposes, then there is not a lot to be done. P10 ignored what BYU brought to the table and focused on other criteria; B12 may do the same.