The PAC has zero financial incentive to add TT, TCU, KSU, Okie State or Baylor. None of them bring enough TV markets and followings. Best they could hope for would be associate members in football only, at which point, BYU would be ahead of many of them.
I could see the B1G taking Kansas and ISU ten years ago but they could be less attractive under a streaming model. WV is really at the mercy of the ACC.