The game passed him by. Only way to win today is to pair up a QB w an offensive coach that's willing to gamble a bit on 4th down and tells his D Coordinator to sell out for the +/- in possessions.
When he had a young Roethlisberger they were a contender, with an old Roethlisberger or a rotating cast of average QB's they weren't. Simple as that, give him a good QB and he'll have his team in the hunt.