Benjy Sarlin has an excellent piece explaining that, because Rep. Paul Ryan's budget proposal eliminates the Affordable Care Act and it's ban on discrimination based on pre-existing conditions, those Medicare vouchers are going to become fairly useless in short order:
Unlike the Affordable Care Act, which mandated that millions of young and healthy Americans purchase insurance with government subsidies, the Paul Ryan plan would instead bring the oldest, sickest, and least profitable demographic to the table. And with the CBO projecting that the average senior would be on the hook for over two-thirds of their health care costs within just 10 years of the plan's adoption -- a proportion that is projected to worsen in the long run --- the government subsidies backing them up may not bring in enough profitable customers to make things worthwhile.
"If reimbursement rates are too low to provide basic benefits, they'll tell the government, 'You do it,'" one insurance lobbyist told TPM. "I don't think they can require they lose money, they'd just pull out."
I made this point earlier in response to Jacob Weisberg's gushing praise for Ryan's Medicare vouchers. This is why there's a mandate in the Affordable Care Act. Insurance companies can't make money if people wait until the last minute to get very expensive care. And they're not going to want to insure the elderly, since they know they're going to lose money doing so. This is why we have Medicare in the first place.
Although hey, since seniors vote, under the scenario in which Ryan's plan passes, I can imagine the American people being ready for a single-payer health-care system in about five years, give or take.