I think the confusion is that from Texas's viewpoint, the ideal pod and 3 permanent rivals look the same.
That's not the case for the rest of the conference.
For pods to work, they would have to add additional protected crossover games since the top rivalries don't all fit in the same 4 team buckets.
Let's just go ahead and make some pods:
Texas - Oklahoma - A&M - Arkansas
Alabama - Auburn - Tennessee - Vanderbilt
Florida - Georgia - South Carolina - Kentucky
Missouri - LSU - Ole Miss - Miss St.
This is a great pod solution for most rivalries but it kills Auburn-Georgia game, so it's pretty much a non starter. Crosspod rivals would have to be locked down as well.
By having a single 16 team conference with no divisions or pods and with each having their own personal set of 3 rival games, you secure more rivalries and you can secure the quickest rotation. It's like each school has their own personal pod.