The CBO has a new estimate of the budget savings from raising the Medicare age to 67. Here it is:
Please note: this is not percent of GDP. This is actual dollars. Over the next ten years, raising the Medicare age would save the government a whopping $2 billion per year on average. Austin Frakt and Aaron Carroll give the nickel explanation for why the number is so low: "The more people you kick off Medicare, the more you get on Medicaid. That increases federal expenditures. More people will also need exchange insurance, too, which means more people needing subsidies....And we’re not even counting the increase to state expenditures for the added Medicaid, the increased cost to employers who have to provide insurance, the increased cost to all Americans in higher premiums for adding those elderly people to the private risk pools, or the increased out of pocket expenses to those seniors."
Bottom line: raising the Medicare age to 67 accomplishes almost nothing. And if you take into account the increased costs in other areas (Medicaid and private insurance), it's a net negative. This is a zombie idea that needs to die once and for all.