The idea that we'd do away with a democratic state and replace it with all-volunteer contracts and shit, it has absolutely no resemblance to reality at all. It's an even bigger fiction than a communist paradise, from each according to his ability and all that.
BUT...my ideal world (for simplicity's sake, star trek--post-scarcity, people can explore and make art, etc) is also fiction. I get that. I don't think we're there, of course, though I'd like to see us get closer.
The difference between our aspirational fictional worlds is, whenever people take steps toward yours (think America in the late 1800s, which is probably the best proxy for the libertarian paradise we could look at in the West), lots of people suffer. Private charity simply didn't--and wouldn't--work the way libertarians think it would/should. Life is hard for a lot of people, and shitty, and we've moved beyond that because it doesn't have to be a cruel world like that.
But when people take steps toward my ideal post-scarcity world (think, broadly speaking, Scandinavia, or even anywhere with universal health care, like Canada), it actually kinda works. Health care systems get funded, people can be artists without starving. People suffer less.
Maybe you prioritize the libertarian ideal of personal freedom (which is not what I'd even consider freedom in any way) over the suffering of a bunch of people, and hey, that's your prerogative.
But looking at the outcomes of one or the other, man I know where I throw in.