For the record, I'm not in favor of a single-payer system.  But I'm also not a fan of much of the rhetoric that I hear against the concept.

In particular, I have always wondered why those advocating for the strength of choice aren't presently railing at the lack of payer choice for both physicians in patients in so many places.  I remember my first time confronting this when I was in Rochester talking to some practices about insurance negotiation and they asked, "What if the plan represents 75% of my business?"

How, on earth, is a plan covering 75% of the lives in a given metro area, or state, not an acute example of restraint of trade?

The AMA wonders too.  From a sadly eye-opening article:

One insurer held 70% or more of the health plan market share in 24 of 43 states measured, up from 18 in 42 states in the previous year's study. In 92% of the 313 markets in the report, one insurer held at least a 30% share.

Read the rest of the article - crazy!  Look at the concentration in some of those markets, so often by the local BCBS plan.  60-100%!

If I were in charge of health care reform, this is where I'd start.