>>Medicare premiums are indexed for inflation.

Worth noting that underwriting is not inflation adjusted, it's risk adjusted; and that 30% of liable parties don't have their contributions waved in other such schemes.

But no matter how much was paid historically: how much was put aside?

If no reserves were built during those early Medicare decades when every $ put aside could have blossomed into the thousands of dollars, wouldn't workers in their 50s now need to pay Medicare the equivalent of 100% of their standard health insurance premium for every extra year they'd like to be covered?

This disastrous expectation is avoided if the populace pays premiums through their young healthy days so that their surpluses can be put aside, not spent. This was the promise of Obamacare, and it *would* have worked and been impossible to reverse had they stuck to their guns on individual mandate. That, and if surpruses from the pre-65s were dedicated to funding their eventual need for Medicare rather than bumper dividends as Medicare's deficit grew. But we've had that conversation before.