The libertarian approach is a very symmetrical one: the non-aggression principle does not rule out force, but only the initiation of force. In other words, you are permitted to use force only in response to some else's use of force. If they do not use force you may not use force yourself. There is a symmetry here: force for force, but no force if no force was used.

There are any number of models artists can use to profit off of their talent and artistry. It is not up to the state to protect them from competition. Musicians can obviously get paid for performing and having their music copied and "pirated" helps them in this respect by making them more well known, more popular.

In a market economy with the division and specialization of labor, people use others as means to achieve their ends. This is the essence of market cooperation.

The roots of copyright lie in censorship. It was easy for state and church to control thought by controlling the scribes, but then the printing press came along and the authorities worried that they couldn't control official thought as easily.

The basis of self-ownership is the fact that each person has direct control over the scarce resource of his body and therefore has a better claim to it than any third party (and any third party seeking to dispute my self-ownership must presuppose the principle of self-ownership in the first place since he is acting as a self-owner).

The Austrian theory of subjective value teaches us that there are many ways to incentivize or motivate or induce someone to commit an action for you: you can promise sexual favors, promise to pay money, hire someone, and so on. Also, there is no reason to think that both the boss and his underling cannot both be 100% responsible: in the law this is called joint and several liability.

Artists are just entrepreneurs. It's up to them to figure out how or if they can make a monetary profit from their passion − from their calling, as I discussed above. Sometimes they can. Musicians can sell music, even in the face of piracy. Or they can sell their services − concerts, etc. Painters and other artists can profit in similar ways. A novelist could use kickstarter for a sequel or get paid to consult on a movie version.