If you are that paranoid basketball isn't the only sport rigged. Why do you think in the NFL hardly any new teams make the Super Bowl? If there is a new team from the conference there is almost a guarantee that the other conference's team has been there before.
Do you mean "hardly any new teams" as in the same teams make the Super Bowl every year? Couldn't be further from the truth, NFL has had 9 distinct teams in the SB in the last 5 years. Or do you mean expansion teams? If you mean no expansion teams, then the answer to that should already be clear. Regardless, I do believe that some NFL teams, namely the Patriots, Cowboys, Steelers, and yes, Packers, get more calls than other teams.