Of course, there are offenses that use the pass as effectively as a run to work the clock. The Packers put the ball in Rodgers' hands because he's that good. Unless the line is total crap, and the defense either is good enough to generate instant pass rush, on average, having Rodgers pass the ball is a better choice than handing it off. Especially when you draft linemen to pass pro. The run is a change of pace, a way to keep the defense honest. You run just enough so that the defense has to be honest.
There are a few games I recall where Packer opponents basically keyed on pass defense and destroyed the Packers. But those defenses (Giants, Arizona, Seattle) could reasonably defense the run without keying on it at all.