The BIG just friendzoned them and they'll simp for it.It's a bluff to keep them from jumping at a Big 12 lifeline.
Even if both PAC schools were valued at approximately what the rest of the league is getting, most of B1G membership knows TV exposure for them falls under their deal if they add more mouths to feed with a fixed number of media slots. They will be interested, but not until the next big media deal rolls around and they see how their more preferred options turn out.