Actually I think that’s a pretty good example of what confuses me about this usage of “free”. Usually when I call something “free” I am making a claim about who pays for the thing, but as you pointed out, in this case it has something to do with who is billed by the service provider.
> In that way, a society organizes that no one has the existential threat (financially or medically) of prohibitively high cost.
IMO, no current Earth society comes close to that criteria. For example, if someone has a currently untreatable disease, then isn’t that just saying the cost of treatment is prohibitively high? ie, the cost of hiring scientists, renting lab space, running trials, etc.