BYU was only at about $10M/yr with ESPN
Notre Dame is at $25M/yr with NBC (deal is about 10 yrs old). Though they're reported to be going up to $55-$75M/year next time... still a pittance to the $130-180M/year they'd be worth to the B1G. Recall that USC/UCLA together were worth a reported $200M/year together to the PAC12 or B1G... with USC being probably ~70% of that.
Network partners take a big risk signing a contract with one team because if that team stinks, they're stuck airing games that won't draw much interest. That risk is mitigated greatly when media partners do a contract with a whole conference because SOMEBODY will be ranked and having a good year and draw eyeballs. Plus they'll have the bigger brands/better teams for both home and away games (something that Indy contracts can't offer)
BYU went with ESPN at a major discount because of security and exposure, and it worked out well in the end. BYU also had absolutely NO leverage and had to do whatever ESPN said.
But people who quote that $10M/year as representative of BYU's media value within a conference are being disingenuous.