The most obvious reason is that the Colts and the Titans aren't better than the Jets or Vikings last year, yet the Bills lost with Poyer and Hyde in the game.
If you are now saying maybe they would not be undefeated, possibly 8-1 then edit or delete the thread. Other than "Johnson taking horrible angles" you've given no cogent argument why with Poyer/Hyde, the Bills couldn't beat teams like Tenn and Indy, but without them, the Bills can't lose to the Fins or Vikings (or possibly the Jets?). Or something...