Why hasn't the age for signing up for Medicare changed to coincide with the eligibility date for drawing social security?

Your question points out a problem with many federal laws: They're often inconsistent. Even though the age for eligibility for Social Security has been raised from 65, this is still the age at which you must enroll in Medicare. In fact, if you don't enroll in Medicare Part B when you're first eligible, you may be subject to penalties when you do enroll (although if you're covered by insurance at work, you can delay enrolling in Medicare Part B without a penalty). I suppose we should just be happy that the age for eligibility for Medicare wasn?t raised, because being able to enroll in Medicare at age 65 usually brings significant health insurance savings.