This is, of course, very demeaning. The inference here is that at 80 years young, grandma and grandpa are the picture of senility. If this were true than I doubt they could even get themselves to the doctor, unless they have family to take care of them. And if they have that, Medicare is moot.
But, beyond that, I believe the more "humane" solution would be treating people as humans and letting them make their own choice instead of treating us like mindless cattle. Starting right now, let all citizens including current Medicare recipients choose between current Medicare, a voucher system, or opt out all together.
Better yet, let everybody opt out of all entitlements and live our life out from under the thumb of government. That seems the most humane to me.