You can't criticise free markets where there is no market, let alone a free one.

"Supply and demand" is not a free market claim, it is accepted by everyone.

I'm just pointing out that the NHS exchanges monetary cost with temporal cost - you're paying with your time rather than your dollars, for access. You're also paying dollars via tax, but that's unrelated to access.

A nation can accept or even demand this trade-off, and many do - but support tends to drop when it is made explicit.