Can the Competition Fairy control healthcare costs?

As I've explored in the last three posts, the Medicare reform plan in Ryan's 2013 budget blurs Democratic attack lines because it looks very much like an Affordable Care Act for seniors (who, er, already have affordable care) while staking an at least ostensibly credible claim to preserve the Medicare guarantee.

The simplest counterargument was just voiced by a Florida voter to Washington Post reporter Felicia Sonmez: if it ain't broke, don't fix it. The counterargument is that Medicare is broken insofar as its cost to taxpayers has wildly outrun inflation and threatens to bankrupt the federal government.  The debate boils down to the best means to control costs while preserving the Medicare guarantee.