Social Security isn't a Ponzi scheme in the sense that there was fraudulent intent. Nevertheless, a lack of political will to finance current benefits does burden future generations. "Adjusting benefits downwards" won't sit too well with people who worked 30 or 40 years and expect to enjoy a certain standard of living.
Why Was Social Security Designed Like A Ponzi Scheme? https://www.forbes.com/sites/johngoodman/2015/08/13/why-was-...
Is Social Security a Ponzi scheme? "Social Security has a funding gap equal to 0.7 percent of GDP over the next 75 years. We could wipe that gap out by lifting the payroll tax cap (right now, payroll taxes only apply to the first $107,000 of income) or by adjusting benefits downwards." https://www.washingtonpost.com/blogs/ezra-klein/post/is-soci...