I think this is mostly a problem with state funded healthcare budgets being cut (relative to population demographics) in these countries. If the UK or Spain spent anywhere even close to what the US spends on healthcare (per capita), I have no doubt that it's healthcare provision would be just as good. In the UK, healthcare provision was notably dramatically better 20-30 years ago under the same system (except for less private finance).
I don't think so. With state funded healthcare you get rigid rulebooks and policies. In the capitalist-ish US model, if you are a successful advocate then you can get better than average care because there's enough flexibility in the system (in many cases, physicians can individually decide to over-extend for one patient if they choose to) to allow for this. Having a private payer market absolutely helps here.
Having care depend on "being a successful advocate" does not sound like a good thing to me! Albeit it's probably impossible to avoid entirely. We want good care for everyone.
I'm mostly familiar with the UK system, but medical professionals make pretty much all the decisions here, with a large degree of discretion according to their professional judgement (and they never have to adjust or delay their care based on whether you can pay). Except for some particularly expensive treatments (think CAR-T for cancer) which are not available at all in the state funded system. But you can still pay for those privately if you want to.
> With state funded healthcare you get rigid rulebooks and policies.
We could just not do that. If you change the flow of control certain problems solve themselves. Think about a landscape where government funding multiplies the patient dollar, for example.
The problem is that it always happens. There's no such thing as comparable funding.