From the moment that Georgia and Oklahoma won that Supreme Court case that reverted control of TV monies from the NCAA (the old CFA) to the conferences was when the Big East was basically doomed. That was when football got on track to be the massively disproportionate revenue generator that it is today.
IMHO, the only real shot the Big East had was to have been VERY proactive when SU, Pitt and BC gave them an ultimatum back in the late 80s to form a football league (I *think* that came after PSU announced they were joining the B10, but could be wrong). There was a moment when it was possible (not sure how probable, but possible) for the Big East to have created a football league that would have included some of the usual suspects (SU, BC, Pitt, Miami, Rutgers, Temple, WVU, VaTech) along with major indies of the time (Florida State, Louisville). Basically, the BE football league just didn't quite go far enough, and then the haphazard way the BE added "full" members didn't help (Miami at first, then RU/VT/WVU later with a long probationary period, and the naive ND deal).
Most importantly, the league needed a strong leader who would have told the hoops schools to shut the hell up, and be lucky you're along for this ride. Instead we kow-towed to them constantly by offering half-measures to the football schools, and the rest is history.