All the vitriol and hatred for BC aside.....here is my take.
As others have mentioned, college sports is just not as big of a deal in the Northeast as it is in the rest of the nation. But where some see a place that is essentially a wasteland for college sports (only really one successful program in the region being UConn M/W Basketball) I see an opportunity.
In New England, I really don't think most people see BC and UConn Football as "bigtime". BC gets some name programs in town, and they have produced some fine NFL QBs but they have never really been an "elite" program. It's also clear that getting into the ACC never gave them a big push in that direction, in fact they have basically regressed for a ton of different reasons and so has UConn for that matter.
So all you have is BC and UConn. Whether one or the other can deliver the whole region is debateable.
UConn has indisputably has the strongest Hoops program in the nation. It's completing a $40 Million basketball facility with private funding.. It's upgrading hockey and is Hockey East. Football is floundering but it can only improve from where it is now.
BC has the best Hockey in the nation. Tasted success in basketball, tasted greater success in football but has a small fanbase regardless.
What happens if the B1G decides to really shake things up and invites both UConn and BC? Their 6 team Hockey conference is instantly bolstered, to say the least. But what it really gets is the chance to integrate the last major market in the US that really doesn't care college sports at the moment.
The thing of it is, people in the northeast generally think that elite college football happens somewhere south and west of it in some flyover state or Florida, California or even Oregon. But if you could possibly bring an entire region into that fold by adding two schools then goodness, why wouldn't you explore that?