Ya know, having used quite a bit of open source software, I gotta say, most of it is far inferior to something you have to pay for. And it's obvious why.
I can generally go and hear some live music for free, as well, but it's usually not nearly as good as the music with a cover charge, or god forbid, a ticket.
Hey WW, would you like it if I copied all our articles, crated my own blog, and got my own advertisers to pay for it? It would require nothing out of me, really, and I'd profit off of your writing, your thinking, and your work. Given the size of the internet, who would know? Perhaps some would eventually found out the original source, but many, many, many others would not - and that's something anyone who's spent any amount of time on the internet should know full well. Things are copied all the time, when it's illegal, and no one's the wiser. One reason people are able to trace it back to the original source is becuase of sourcing, copyrights, etc.
There's something I've noticed about libertarian theories; they often hinge upon some sort of government or some sort of theory they don't like to support it. It's like environmentalism, where libertarians insist the a strong personal definition of property rights would solve everything, but in order for that to solve anything, you have to have a fiat judicial system - i.e. government - in order for it to work. The same goes with IP, where every example given is possible due to at least some conception of IP; it's argued that people would favor the original artists, etc; but that favoring is only possible due to knowledge, which is only possible due to IP.