Bill,
Apples & oranges. The Packers' championships were the equivalent of a Conference Championship these days. There just wasn't another conference to play against, until 1966. They also didn't have to endure a playoff schedule like the teams have to now. It was a different league back then, with shorter seasons. Not to take away from their greatness during their era, but you just can't make the comparison between those championships and the Super Bowls.
Actually, prior to Free Agency and the Salary Cap, it was much easier for the great teams to retain their rosters, and dominate year after year. I don't like league parity - it's just so watered down now. I miss those powerhouse teams of the 60's, 70's, 80's, and early 90's.