Expansion does the B12 no good unless they stole someone from ACC (Clem/FSU/VT) or Pac12 (Zona Schools). Other than that, there is no expansion that would benefit the conference other than to water down the content and lower the TV Payouts.
With respect to LHN...UT holds all the cards. Why would they give up $8-$15Mil a year + TV payouts from the league to benefit the rest of the teams. Imagine living in a subdivision with your neighbors and you had high speed internet, huge download/upload with fiber optic lines, enables you to run your business from home, stream media, etc, and keep the kids happy. Meanwhile the other neighbors were only able to get dialup AOL with a modem. Top speed of 56k. Now, the neighbors come to you and ask you to give up HS internet for the sake of the subdivision. That's what UT is dealing with. They have a business/program to run. Its why they aren't in the PAC12