Well, that's fine - what I've written isn't a manifesto, and it's not meant to be. Mind if I answer a few of your points? It helps me to distill my thoughts to write them down. I'm asking these questions about anarchy as a way to think through it myself.

You seem to presume no other routes existed or can exist.

If other routes existed, why wouldn't they be subject to the same tragedy of the commons as the river in my example?

Also, how is it beneficial for the toll setters to have tolls that throttle a route to extinction?

It's not beneficial, that's the point. The toll setters are not individually setting tolls that throttle the route, they are collectively doing it in an un-coordinated manner. As I explain in my story, they can't coordinate because if all of them lowered rates, any one of them would be incentivized to raise rates to capture more revenue. This is called a Tragedy of the Commons.

someone would drive a road through to bypass the river route if it became too pricey.

Are you proposing that the way to fix the dilemma is to have one single entity own an entire road all the way? One single entity, like, say, a government? You say that toll roads are cheap today - well yeah, most toll roads today are publicly-owned.

Before it got to the level you describe, someone would sell their barges and start negotiations with people to drive a railway between the two towns.

Maybe - but even in the modern US with its strong central government, a huge number of railroad projects are shut down because people who live along the route don't want trains going by. With no government, no possibility of eminent domain, no central authority who can dole out compensation for peoples' land, this problem only becomes harder.

Just because you can't think of a way doesn't mean no one can.

The thing I find interesting is that I've never read a single account of how a Tragedy of the Commons can be solved without some level of central coordination. Even the anarchists' best answer is "solve it with a blockchain!" That's not anarchy, that's cryptocracy. People still end up with solid constraints on what they are allowed to do.

Your example of what voluntaryism leads to is so simplistic it becomes a complete strawman of that system. Got logic? Because this ain't it.

So much for a civil debate, right? I never said this was a simulation of reality; I said it was a parable. Someone else here accused me of writing a "just-so story," and that's fine. You want formal logic and math? I can do that, and probably will. Follow me and watch for my future posts on it!

Anyway, thanks for reading this far. Follow me for more violent pro-government communist drivel. ;)