You make a good point, though Medicare eligibility is generally limited to age 65 or above, kidney failure can also make an individual eligible, regardless of age. Some FReeper should dig into the official numbers and chart which groups are getting payments, the geographic distribution of payments, etc. for both Medicare and Medicaid (the low-income, means-tested health care program).
Per this link http://www.statehealthfacts.org/comparetable.jsp?ind=292&cat=6 in 2004 15.7% of Medicare enrollees were under 65. Given the fast-increasing rate of diabetes and resulting kidney failure, I expect it’s higher now. But more significant is the demographics of the underage group, which is certainly overwhelmingly the low- or no-tax paying segment of society, since that demographic profile is already well-established as very disproportionately accounting for the high incidence of diabetes.
It would be interesting to see what percentage of Medicare-covered people actually get out more than they paid in over a lifetime (including the investment return they would have gotten, had they kept the money and invested it in conservative and safe instruments). I’d be surprised if at least 75% aren’t taking out more than they put in. Classic case of people voting themselves other people’s money, with politicians’ encouragement.