IMO the Big12 must win the race to a strong, although maybe middling, 16 team conference. That is the direction we are going.
Also I bet ND would be willing to be in a ksu/ku/isu pod if there was some sort of permanent rival system like the SEC has where they got Texas, OU, FSU or something.
It's not the direction we're going. It's not economically feasible in the current model.
It makes the most sense logically, symmetrically, and logistically, but financially, you won't find enough schools that will push your value to the point where 16 teams make financial sense.
Besides, the Big Ten can't find 16 schools that fit their criteria for admission and provide economic value. The Pac-12 is kind of the same way. Their presidents don't want to slum with major universities like Tech, OU, and OSU due to their academic standards and the stigma that goes a long with Midwestern state schools.
The only conferences that 'may' go to 16 would be the ACC, Big 12, and SEC. The Big 12 and SEC are the only two in that group that could even come close to financially making that work, and the odds of them actually doing so is close to nil.
My guess is that the Big 12 and SEC go to 14, the ACC settles back in at 12 by adding UConn and someone else, and the Big Ten and Pac-12 stay at 12 and use their alliance to swap all kinds of inventory for their TV partners.