Capitalism, and the market, is a wonderful thing... but there are some "leveling the playing field" benefits of single payer systems. For one, if you have multiple companies competing in a cut-throat market, they will be forced to look at cutting employee benefits to gain advantage. Walmart, for example, uses labor practices that force a large percentage of their employees onto the public health care rolls. Another more obvious example is the problems some older companies are having with pensions. United ditched their pension obligations under bankruptcy protection, and now there are stories of GM looking at the same thing. When GM competes with a company in a country that has a single payer system, GM may be at a disadvantage, depending on the relative costs of taxes vs. health care. In addition, a company like United was at a disadvantage to a newer company like Jetblue because they have legacy pension obligations that Jetblue won't have for 50 years. And now that United has ditched its pension obligations, other older airlines like American are at a disadvantage because they still have their pensions to maintain.

One might argue that if none of these single payer systems existed, their wouldn't be this pressure for the US to have one as well. Granted, it would be reduced. But good luck getting other countries to ditch their single payer systems.

Another aspect of company systems is discrimination against those who are likely to cost more. That discrimination is probably mostly age discrimination, but it can also be weight or lifestyle based (obesity, those who are fans of risk taking sports) or even against those with families. The recent Walmart health care memo lead to this type of speculation, for example. We may be a way from Gattaca style discrimination, but its still there. And I'm not saying that companies will discriminate, but as long as their is economic benefit to doing so, some will be tempted.

There are, of course, problems with single payer systems as well, and generally no one is happy with the level of service of their government, but addressing the above problems in some fashion would definitely be useful.