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.