> I do not know about medicare per se, but when social security was designed to support people 65 and over, I think life expectancy was around age 62. So it was designed to support a relatively small number of retirees in their extreme old age. Then people began living longer.

This is true, but the real problems with Social Security began when Lyndon Johnson combined the Social Security fund, then entirely separate, with the rest of the federal budget. Instead of maintaining a very close eye on how much money was coming in and going out for Social Security, there was no longer any urgency to keep that money around. In other words, money taken out of paychecks for Social Security was spent on everything else, and Federal income taxes were paid out as Social Security.