It all started in 1991 when the SEC raided the SWC of Arkansas and the Metro Conference of South Carolina, getting to 12 and setting up a conference title game.
In 1994, the Big 8 took 4 of the remaining Texas SWC schools, leaving Rice, SMU, and TCU to the WAC. They then set up a title game.
Things probably would have stopped, or slowed, but then the ACC took Miami and VT, petitioned the NCAA to let them have a title game with 11 schools (which would have helped B10), but was rejected. That was the moment 12 became necessary for the money. They took BC to get there.
The BXII had problems with Texas, which made teams want to leave. The BE football schools had problems with the basketball onlies not letting them get to 12. And 16 became a potential goal because it could be a way to preserve more rivalries (7 fb, 14 round robin basketball against the same schools every year) and still stage a championship game.
Now its all about markets. We have one, but so does Rutgers. Our football might be too young. If we get into the ACC or B10 we have two people to thank:
1) Calhoun
2) Lew Perkins
We may be either way, but the fact that we have a shot comes from them.