The narrative that social security will eventually bankrupt the country (or the updated version: "it's a ponzi") dates back to its inception 80 years ago and it's been pretty consistent ever since:

https://www.huffingtonpost.com/peter-dreier/post_9910_b_7988...

While the economy has grown about ~400% dependency ratios have gone up about 11% I think. Social security's affordability has always been about political choice - e.g. tax cuts for the wealthy or money for pensioners.