Almost every market in the world has this - if you want and can afford private healthcare, or your employer pays for it, no-one is going to stop you using it. Medicaid alone is more expensive and less effective than the public healthcare systems in other countries and still doesn't provide universal coverage.

It'd be great if there was both but it's not allowed in Canada so the net effect is you get less tail outcomes, both positive and negative. For folks in the US with insurance, it's a big drop in the standard of care and for folks without, it's a big improvement.

One other thing that's not often mentioned is the best doctors tend to move. When my grandfather was super sick, he was next to a man who's 3 sons were there looking after him. They were all doctors and came to the US to practice because Canadian salaries were so low (they too were ranting about how bad the care there was).

That's what the UK has. In fact the free healthcare is better than basic. It's generally very good quality, to the extent that many people don't buy private even if they can afford it.

Medicaid?