In a Ponzi scheme, all participation is voluntary. Social Security is mandatory.
In a Ponzi scheme, there were no limits to how much the participants could contribute. Social Security specifies the exact amount that must be contributed by the participant and the employer.
You are an ignoramus and do not know diddly-squat.
No Ponzi scheme can last 80 years, dolt. When it was invented, the birth rate was much higher and the population was much younger, so it worked quite well. But now the birthrate is below replacement levels, and only immigration can cause the population to grow, which is essential for the consumer economy to continue.