Averages and total contribution are not accurate when dealing with regular contributions over a period of years. Look into how money works in an Annuity, and what that annuity is worth after 40 years of regular contributions. (Hint, the value FAR surpasses the sum of contributions).
SS is not an annuity, nor is it an investment account. Benefit payments from the program now exceed total inputs, for two years running. You may think whatever you like about averages, propaganda, etc., but the fact remains that the program is insolvent.