This is not entirely accurate, vis a vie Boston College.
BC was really good in the first few years of their ACC existence. They got to #2 in the Matty ICE years, but have been fair since, in not winning more than 7 games since 2010, with a 1-5 bowl record, but only 4 losing seasons.
IMO, BC should have been disqualified from conference realignment in 1996, but that aside, their downfall began when Gene DeFilippo got too big for his britches and made the ultimatum to Jeff Jagodzinski, who had the gall to interview with the Jets.
Don't let the fact that they could hardly ever beat UConn fool you on the basketball side. BC was very good in the 15 or so years leading up to the defection, including the Jared Dudley years that straddled the two conferences, but they haven't made the Tournament since 2009 and then fired the popular Al Skinner.
BC might have lost their identity, but the ACC doesn't need them to be good, and they don't need WEEI or The Sports Hub to cover college athletics. The ACC has a solid foothold in the 6th/7th largest media market, where Southern NE contributes to ACCN carriage fees whether it is watched or not.