The price of dealing with an extremist opposition?

There is a meme gathering steam on the left -- whether triggered by Ezra Klein or by multiple people in the know or making the same deduction -- that Obama will accede to raising the Medicare eligibility age as the price for pretty much getting his way on taxes (and stimulus)?  Here's how Don Taylor compressed the logic in a tweet: 

it is only thing Rs have on health. Inevitable & some D political advantages per ACA even tho bad policy

My first thought in response was, "since Republicans always toss in "means-testing" when they talk up entitlement "reform," why not "means-test" the eligibility age? As Paul Krugman has pointed out repeatedly, "Gains in life expectancy have been very strongly correlated with income and class; those with lower incomes and lower status...have seen very small gains in life expectancy." So perhaps eligibility could be tied to income or assets. That might create some marginally perverse incentives, but that only underscores what a dumb idea raising the eligibility age is in any case (it will raise total healthcare spending, as Sarah Kliff has demonstrated).

A backdoor way to shore up the Affordable Care Act?

Before Obama's "grand bargain" with Boehner imploded, many progressives were appalled to learn that Obama had put (gradually) raising the Medicare retirement age to 67 on the table. Swampland suggests that Democrats on the supercommittee charged with proposing a deficit reduction package are doing the same:

Democratic staffers on the Ways and Means Committee on Wednesday submitted a list of potential savings, including some $500 billion from Medicare through tweaks like raising the eligibility age to 67 from 65. The bipartisan task forces of months past have identified a menu of potential savings the supercommittee can mix and match from to reach its goal.

The actual Ways and Means memo, however, reads more like a brief against this option -- and a slap at Obama for proposing it.  It also perhaps hints at the germ of a messy bargain, or rather a kind of subtrigger to preserve these alleged savings, which may be presumed dear to GOP hearts (my emphasis below):

Raising the Medicare eligibility age [by two months per year through 2027, to 67]would be a radical departure from current policy and is only possible if the ACA is retained. If ACA were subsequently repealed or otherwise substantially changed, this policy would result in a significant increase in the number of near-elderly uninsured persons. Even