All right, let me try it this way.
You have a running back who rushes for 300 yards in a game, averaging 10 yards per carry.
Is he elite if in all of his other games, he averages 3 yards per carry and less than 100 yards?
Now, extrapolate that over a career. Cam had one great season last year, which is fantastic. However, his other 4 seasons have been like that back averaging 3 yards per carry.
He's not elite because the pattern of his career so far shows him to be average. If he can build on what he did last year, he can turn that around and become an elite QB. One year does not a career make.
Brady, Romo and P. Manning are elite because they've shown they are among the top QBs year after year. In fact, notice that with Polian and with me that Manning held onto his elite status despite not having an elite year last year. He is elite because he earned that over his career.