To me, this is all about the big 10 wanting acc schools / ND... can't have them now due to the grant of rights. But no need to expand now. They also want to keep ou/tx out of the sec for as long as possible...
So, my take on the big ten's moves
1) Delay ou/tx departures to keep them out of the sec for as long as possible (keep status quo); so, make sure acc, pac do not add any b12 teams, if none of the "Big 8" teams get p4 invites, they will keep the big 12 intact for as long as possible.
2) Play the long game... they are already confident in short / mid term revenue, no need for them to add.
3) Keep pac / acc from making a move becoming a bigger player by forming an "aliance"; also helps them keep sec from gaining control - keep acc/pac on your side by painting sec as the bad guys
4) Once the GoR for UVA/UNC open up, take them and ND, maybe GT or another school (clemson? depends how important aau is).... plus in 10 yrs the gap between acc and b10 will be so big... may be realistic to buy out the last 5 yrs (acc deal is BAD).
Net, acc better be playing the b10... or they get crushed once gor expires. B12 teams may have a shot to join the PAC if they can keep up, make themselves attractive while the b10 waits out the acc GOR.. If Pac is not raided, they will need to make a move to keep up with 20 team sec/b10 leagues.