Simple answer -- $$. No one wants to see Cincy-TCU/Boise-TCU, etc. (Plus TCU already beat Boise last year).
It's the same reason the Big Televen is (undeservedly) going to get 2 teams into the BCS. That's right. Unless the Fiesta Bowl does the right thing and picks Boise, then either Penn State, who has beaten exactly nobody, or Iowa, who may be the worst 10-2 team I have ever seen in a BCS conference, will be in the BCS. This would be over a 2 loss GaTech or Cincinnati. Them's the breaks.
To see how it might play out, click the link with the procedure:
BCS Procedures
Let's assume UT and Cincy win conference and Gators win today to simplify things.
BCS Championship will be UT (2) vs. SEC Winner (1).
Rose Bowl - OSU-Winner of Oregon civil war
Sugar Bowl - gets first pick since they lost SEC winner. They will pick SEC loser.
Fiesta Bowl - gets second pick since they lost Texas. Let's get back to this. Unless Fiesta Bowl uses this pick on Boise, Boise won't get in.
Orange Bowl - gets ACC Champ plus third pick
Sooooo.... who does the Fiesta Bowl pick? Assuming they beat OU, I am going with Oklahoma St.
Orange Bowl - ACC Winner. They won't pick Cincy since Cincy was there last year. They will pick the PSU/Iowa garbage over TCU for $$ reasons, I think. Probably PSU which is even more of a travesty.
Fiesta Bowl. Hmmmmm... Cincy or TCU. Gotta think they take TCU. I hope not, but Cincy travels worse than TCU
Sugar Bowl. Left with Cincy.
So unless one of the bowls has a crisis of conscience and picks Boise, you are looking at:
BCS - UT-SEC Winner
Rose - tOSU - Civil War Winner
Sugar - SEC Loser - Cincy
Orange - ACC Winner vs. PSU/Iowa
Fiesta - Okie Light vs Frogs