How did my fantasy team suck so bad?

Guarantee you didn't use the waiver wire effectively when it came down to it. Both Williams and Jacobs were either hurt or sucking it up the last few weeks. You could have picked up much better alternatives than Mcgahee by season end. Same thing with your WRs. They were once good but then you fell in love and refused to change them out when they started to drop in performance (Steve Smith). Same with Roethlistberger, the Steeler's have been awful the last half of the season. You need to be able to adapt to the changes in the NFL as the season progresses or you will end up in your situation: some players that were once good and then stopped producing more than average points.