They were both in the top 20 at the time; it would have seemed that the winner would make the Pac 12 Title game. So, while I see your point, I think I could make an argument that NO teams left in Pac (or Big 12) matter in that regard. Personal opinion, only the conference title game is gonna break 4M viewers even in a "best of the Pac merging with best of the Big 12" scenario. There just isn't enough of a draw to get 4M viewers for a non-Ohio State non-SEC game.

TCU didn't win its second "BCS" game until after they had already been accepted to the Big 12, right? So they got the call up before even getting a crack at a second game.

On a side note: BYU winning a national championship in the 80's is fairly nationally relevant I would think? I get that conference realignment wasn't big in the 80's but it doesn't get much more nationally relevant than winning a title, right? It was 15 years before they "upgraded" to the MWC. Maybe winning a Heisman makes you nationally relevant...oh wait, they did that too and had to wait 9 years to upgrade. Beat a highly ranked K-State in the Cotton Bowl (at the time was probably the 4th/5th most prestigious Bowl Game). Waited 3 years to upgrade. BYU did plenty of nationally relevant things in the 70's-90's without an upgrade.