Charlie Gard's parents were free to pay for experimental treatment throughout the course of his illness up until the point where legally they were stopped from doing something that was considered bad for him. Here in the UK we have a single payer public health service and privately paid services. People are free to choose which they use.

Even ignoring that fact though, the idea that hundreds of thousands of people should face financial ruin and all the negative societal effects that carries with it because extreme outliers need to be handled separately is an utterly broken way of running a healthcare system.