Before EMTALA their were charity hospitals that were funded by donations and volunteers that would treat people that had no ability to pay. The treatment was likely of lower quality and you couldn’t guarantee that there was one close enough that you wouldn’t die in transport, but you theoretically had access to affordable treatment.
The bottom line for in nearly every country whether it’s single payer, cash only, or what we have there’s no way to afford the best available treatment option for everybody. Ration care which is what happens in Single Payer countries or best care goes to the highest bidder China, Mexico, etc.
Insurance should cover the freak cancer case (40 and otherwise healthy) or the broken leg in a accident. Truly one off events that don’t happen all that often and for many people never happen. Insurance can’t cover the cost of just getting old. We all need to save for that.