For as much success as the regular season saw, the Buffalo Bills playoff run can only be described as a failure. The Buffalo Bills season ended abruptly and surprisingly Sunday with a home playoff loss to the Cincinnati Bengals. It’s a bitter end to an emotional, but successful regular season. But for as much success as the regular season saw, the playoff run can only be described as a failure. And with failure comes self-reflection. Bills coach Sean McDermott refused to address questions regarding possible coaching changes during his end-of-season press conference on Monday. But he did address the failures.…