Both MU and Aggie have sucked for a long, LOOOOOOONG time in the Big 12. MU has been competitive, but at the end of the day, they win nothing. Aggie hasn't really even been competitive outside last year for like the last decade.
NEITHER will do anything of note in the SEC. They'll just get paid well to be a punching bag. The bonus for the SEC is the money they may generate off those media markets, if they can find a way to make money where Aggie and MU haven't. Neither MU or Aggie control or generate much local interest in their markets.