Yes the B1G has a LOT of money right now thanks to the BTN. They should make more in 2015/16 as well will the Big XII, (If it's still around). That being said, here are the current deals as I understand them.
B1G:$1B/10 yrs/12 teams first tier = $8,333,333; $2.8B/25 yrs/12 teams second tier = $9,333,333. With equal revenue sharing, each team should get $17,666,666.
Big XII: $480M/8 yrs/10 teams first tier = $6,000,000; $1.17B/13 yrs/10 teams second tier = $9,000,000. With equal revenue sharing, each team should get $15,000,000. But as we all know, the Big XII doesn't do equal revenue sharing.
So, the B1G and Big XII are both due to renegotiate tier one in '15/'16. If the Big XII is still around, say because they negotiated a deal for a ND, tier one would be very sweet, considering the Pac 12 just got $3B. ND, with todays Big XII deal would get $15M/year on tier one and two, and then add a third tier of say $300,000,000/20 yr, like UT got and now they are making $30M/year by joining the Big XII with today's contract and assuming aTm was gone and ND was the tenth team.
I realize that the chances of the Big XII surviving until '15/'16 if aTm left, probably unlikely. I also don't know how much more Texas gets per year than ISU in the current tier one, but I would assume ND could get just as much which would make up for the difference in /team avg. As well, the new tier one contract WITH ND would break anything the Pac 12 got I'm sure, so the annual $would be much higher than $28M/year.
Confused with the crap above? I'm sure. All I'm trying to point out is that the Big X wasn't that much richer before the BTN, and if the Big XII can limp to renegotiation, it could make more than the B1G per team per year. So if your argument is that the B1G is so much better for ND than the Big XII, I say blah. If your argument is academics, you have some ground there, but Big XII is now slouch, so blah. If your argument is that ND already plays many B1G teams, then you have much more weight. All in all, I think smart people could fit ND into either conference so I wouldn't rule anything out.
So to you know-it-alls, you can stop with your ND will NEVER, EVER join the Big XII, 'cause you just don't know what these guys will do.