The Big 10 gets their network on the basic cable/satellite subscription packages in areas where they have a Big 10 team, so Rutgers was invited to add New York City and New Jersey as "Big 10 areas" -- this meant millions for the Big 10 network in added subscription fees. Basically, Rutgers (and Maryland) was added for their TV footprint and that it is an AAU member, and not because of its athletic department.
This doesn't work for BYU or the Big 12 -- the Big 12 does not have a conference network and, even if they did, BYU does not offer a large local footprint. If the Big 12 did have a network, they would likely go after UConn or other schools with large local TV DMAs.