I think the biggest point of contention is that reasonably well kept and healthy people are receiving little to nothing for their money in the present. eg, I got tons of push back asking for simple lab tests like cRP or dermatology cancer screening which would have been less than 10% of what I contribute to the system. Another time I literally waited in a ER room until my loss of blood made me a triage priority. The amount of resources available due to the market distortions means they have to defer you until you're worse off than when you walked in.
Compare that to fast (always <1 hr, even for non emergency things like a dislocated finger) and reasonable waits anytime I've been to a hospital in the US. Mind you I've also probably spent a total of $40k (not my portion) in ~8 yrs of residency between insurance costs and copays, more than half due to a heart attack scare and ER trip that ended up being myocarditis from the vaccine.
So what's my point in all this rambling? I think there's a ton of unlocked value in the US system to do more preventative care, but the US is anti-paternalism and often lets people do stuff that costs them in the long run (unwittingly or knowingly). But there's a hidden truth to Canada's system appearing so rosy -- at least as the payer and consumer I feel I get more for less in the US. Whereas in Canada you have better average outcomes because you take marginal care (eg preventative tests) from those who pay, and give it to those who cannot pay but may have a marginally more improvable conditions (eg bleeding out, having a heart attack).
[1]: compare to about a quarter of that in medicare on much higher earnings