You say excuses, but many other top QBs routinely have multiple things going for them.
Brady - Excellent WR corps for most of his career, defense some years, good to great run game usually, and same coaching staff and system.
Peyton Manning - Great offensive line, WR corps, same coaching staff mostly and system. Run game off and on...defense usually subpar.
Aaron Rodgers - Run game off and on, defense off and on. Great receiving core and offensive line usually hurt...and coaching staff and system the same.
Drew Brees - Same system, coaching staff every year. WR Corps golden. Defense more poor than good, offensive line usually good, and running game pretty good.
These are probably the top 4 QBs of the last decade. Lets now give them the Stafford "excuses"
For a real life example. Tom Brady last year. Sure he had the coaching staff and the system that has always been there. Defense actually gave up 3 less pts per game than in 2012, but it still was a poor defense. And had a top 10 run offense. But, his WR corps were subpar and injury plagued. His offensive line played poorly and had injuries. He in return had a very "stafford type" season. His accuracy dipped 5%, and his QB rating dropped about 8-13 points down to the mid to upper 80s.
Now this may not be an actual phenomena but it could be.
Take Aaron Rodgers. Take away Jordy Nelson and Cobb...I think he may do worse. Just a thought.
The main question with Stafford and these "excuses" is when has he had a full year where he had at least 3 of the following
- A good Coaching Staff and offensive system that has been in place for a number of years.
- At least two real good receiving options that play the whole year
- A top 10 Running Game
- A top 10 Defense
- A good offensive line that aren't plagued by injuries.
Because looking at the better QBs in the league, they seem to need at least 3 of these things to do well.