The cable subscriber model for conference networks was a key factor ten years ago, so it was about getting team within footprints of large metros. That's the main reason Maryland was added, and the only reason Rutgers was added.
Cable subscriber model is now dying, so it's a lot less important now. Rutgers would definitely NOT be a take, today, for the B1G. Maryland probably not, either.
But adding teams to a conference is basically a no-cancel, no return kind of thing. The B1G is stuck with them, now.