At the core of the issue is the fact that providers will not deny you care because of the Hippocratic Oath. If you show up to an ER having a heart attack or with a compound fracture, they're going treat you regardless of your ability to pay for the services.
The costs of treating those who cannot pay must still be paid - doctors, nurses, orderlies, drugs, tools, and so on - and so those organizations increase the price of services to account for the deficit.
In the 1970s Nixon signed into existence HMOs which added yet another consideration for prices - one of the ways these entities profiteer on healthcare is by creating arbitrary redemption rates for providers that build in a guaranteed percentage into their bottom line for investors.
By the late 90s, that system had invented 'pre-existing conditions' and was driving profit by simply denying expensive procedures, and by the 2000s was increasing -their- price to consumers by 20% or more year over year - and that was all while receiving massive government subsidies.
Central payer systems eliminate the profiteering, cut out middlemen who pad their stock values with our tax dollars, reduce the percentage of GDP committed to healthcare (reducing total cost to we the people), and make healthcare services and necessary drugs far more accessible.
And if we follow the UK model of a two-tiered system, you don't even have to give up your overpriced for-profit healthcare if you truly prefer the immediacy it provides.