Is raising the eligibiliity age for Medicare a good idea?

There is lots of talk about "How to fix Medicare?" and one of the options being discussed is simply to increase the age at which one may qualify.  The following graph (from The Incidental Economist, see here) should give some pause to pursuing this option.

Aaron Carroll at The Incidental Economist says:

The life expectancy at age 65 for those in the bottom half of earners has not risen at nearly the rate of the top half of earners. So raising the retirement age will impact the total benefits given to lower income people more than higher income people.