There are some major flaws in your argument here. First, remember that someone creating content of any kind, digital or not, is not automatically entitles to compensation. Even in the days of CDs, someone had to physically buy the discs for them to make money--and if the music sucked, they didn't. There are plenty of reasons why someone would create content without expecting to be directly paid for it: reputation, enjoyment, contributing to the sum of human knowledge and the human experience. Why do scientists do research? Yes, they are salaried, but they are not getting paid for their "content" specifically; their research is released into the world for free (hidden only behind journal pay walls, a separate issue).
As for your comment on non digital domains, it suffers from the same flaw as previous arguments above. When you get your teeth cleaned or your car towed, it is NOT true that the dentist for example could still clean other teeth. He can in the future, but during the time he cleaned your teeth, he could have been cleaning someonje else's teeth but wasn't because he was cleaning yours. There is an opportunity cost there. With digital files, there is no such cost. It makes no difference whatsoever to a file or its creator whether it is shared one time or a thousand, since the creator isn't doing anything differently nor investing incremental time or money for each additional share.
As for your comment on non digital domains, it suffers from the same flaw as previous arguments above. When you get your teeth cleaned or your car towed, it is NOT true that the dentist for example could still clean other teeth. He can in the future, but during the time he cleaned your teeth, he could have been cleaning someonje else's teeth but wasn't because he was cleaning yours. There is an opportunity cost there. With digital files, there is no such cost. It makes no difference whatsoever to a file or its creator whether it is shared one time or a thousand, since the creator isn't doing anything differently nor investing incremental time or money for each additional share.