If the Big 12 went exclusively west and took 4 teams from BYU, UNLV, Boise State, Air Force, San Diego State, Colorado State, Fresno, then allowed those new teams to grow and become "P5 level" (regardless of future affiliation, the Big12 would be a boost for any of these teams), then it would be in a much better position down the road to poach or combine with the Pac12. Expanding eastward is expanding into SEC and ACC country. Why go be 3rd fiddle when you could go west and be 1st or 2nd? Going west could possibly net you all of Texas and get into California.

My money is that the Big 12 does just about what Gustav suggests, but it seems like a lost opportunity.