I unsterstand the relative nature of 'greatness' to its time or era as you say. I simply don't regard the championships of the Packers prior to a legitimate form of serious competition in the football world as highly comendable except in relation to their influence on the popularity and progression of the sport. If you truly consider admirable greatness as an extended period of completely uncontested winning over teams that were ridiculously inferior fledgling teams, then so be it - that is your opinion and I can't take that from you. I simply believe that such victory is negligibly noteworthy compared to the dominance of such teams as the Celtics for example, who exemplified true dominance in a highly competitive sport.
Since Super Bowl II, marking the end of Green Bay's extended period of uncontested winning over a sport that held no parody whatsoever, the Packers have won...what...one Super Bowl?
So...
That's one amazing example of true domination vs...
5?
San Fran, Dallas, Pittsburgh, maybe even New England if they keep winning enough - We RUN this show. Game over.