Why?
1.) The Bengals had scored fewer than 20 points in 9 of their last 12 games prior to yesterday, so there should be no surprise that they struggled scoring in their first game of the year.
2.) The Bengals drafted a receiving TE in the first round of the draft and signed T.O. Throwing the ball a lot makes sense as a general rule, although.....
3.) Crappy coaching by the Bengals led to far too many passes in the first half and nowhere near enough runs. When they did run, they often guessed wrong, as in the case of the Benson fumble, when the Bengals ran into a blitz and ended up going against an 8 man rush. Once New England stopped blitzing and settled into the cover 3, the Bengals were much more successful running the ball.
Anemic offense + transition from running game to a more pass oriented system + lousy coaching = Sunday's Bengals.