So, Brady threw 67% of his 612 passes this season to Welker, Gronk and Ahern - who were catching them at a combined rate of about 72% and who scored 33 of 39 receiving TDs - only because there wasn't a viable alternative?
For comparison, here are the catch rates of some of the top WRs in the league for 2011:
61% Calvin Johnson
71% Jordy Nelson
64% Cruz
63% Wallace
75% Colston
61% Malcolm Floyd
68% Laurent Robinson
57% Nicks
57% AJ Green
52% Fitzgerald
66% Jennings
61% Dez Bryant
52% V-Jax
61% Steve Smith (CAR)
71% Lance Moore
58% Marshall
69% James Jones
56% Roddy White
56% Antonio Brown
67% Meacham
66% Maclin
54% Boldin
48% Brandon Lloyd
Not many guys on this list catching at 70%+, much less THREE of them on the same team.
Branch finished the season at 57%, but was catching at a rate of 65% up through Week-11, or thereabouts, when his percentage of Brady's targets to him began to dwindle fairly quickly. "He's old; he wore down; he wasn't getting open," seems a pretty lazy way to analyze this result, since some other things changed as well. For one thing, Branch didn't appear to be, going over the middle as much - his routes weren't taking him there, but actually seemed to be keeping him outside the numbers and even deep a higher percentage of the time (more difficult, lower-percentage completions anyway). And, as others have observed, defenses began pressing him (and Ocho) at the line more often. Also, he WAS getting open on some of his shorter sideline routes (as was Ocho, when he got into games), but Brady wasn't going to him - um, possibly because he was having so much success throwing to the three amigos over the middle.
As far as Ocho is concerned, he's not the only accomplished veteran to have been slow to fit into the passing attack during the BB/Brady Era. In fact, his 2011 stats put him in the top 30% of first season production among ALL three dozen or so wide receivers that BB has acquired since 2000 (UFA or draftee) and was greater than even what Jabar Gaffney produced in HIS first season with the Pats. Again, Ocho was the FIFTH guy down the passing target depth chart behind 3 guys who were catching at 70%+, plus an old favorite Brady target in Branch. I mean, I don't understand why folks were expecting Ocho to somehow set the field on fire, the way things played out over the season with Brady's top three targets. Was Brady going to go away from guys catching 70%+? Was he going to throw the ball even more than 611 times? What's going to happen in 2012 if Ocho is replaced on the by some new hotshot WR (with less experience practicing in the Pats offense than Ocho has under his belt now)? Really, how "good" does this new guy have to be to take targets away from the 70-percenters? Or is everybody just figuring that Brady will throw even more?