Because the Big Ten doesn't want any of those schools.
Just to add to this, the Big Ten has major interest in extending it's reach towards the East. Hence why many think Rutgers is a lock even though they will not deliver the NY market. It's probably why the ACC moved fast to get Pitt and Syracuse.
It makes more sense for the Big XII schools (Texas, OU, OSU, TTech) to go West, logistically. Though Football is king, they have to consider sending non revenue sports from Austin to Happy Valley, etc.
The big fish for the Big Ten is and has always been Notre Dame.
It will be interesting to see where TCU, Kansas, Louisville and others land. MWC with TCU, Boise and Kansas wouldn't be too bad.