Sorry, no. I have no knowledge of other countries' healthcare systems, as I only work in the US one. I should have been clearer that I was referring to the US. The US government programs (Medicare and Medicaid) get drugs at a discount (at least, they simply refuse to pay more), which is compensated by the distributors charging private companies more.
One of the problems with these discussions is that the US doesn't have a purely capitalist private system. A very large percentage of it all is already socialized in the form of Medicare, Medicaid, and VA. Complicating matters further is that the patients themselves participate in both forms--almost everybody over 65 has Medicare as their primary insurance, but can and do have secondary insurance which is generally private. Which, given the demographics of the typical oncology practice (skewed to the elderly), means that for any given patient we'll be filing claims with both a commerical insurer and the government program.
We already have a partially socialized medical system, and we have problems with it. Ditto the commercial side. That's why Americans tend not to believe in the amazing benefits of socialized medicine. It goes against our current experience. And telling us that if we just converted all the way it'd be good...well, you can see where we'd need more than trust and some internet arguments for something that big.
eta: Oh, and I forgot the horrors of "managed Medicare". It's commercial insurance that pretends to be Medicare, or Medicare programs run by commerical insurers. It manages to combine the worst aspects of both worlds, pays little, and late, and is immensely popular because the companies market it well. They're making a mint from it, but nobody else is.