I don't think the 19th C music example is not as daft as it first appears. Everyone's still free to copy the original 19th century score, or copy 19th century copies of the original score. If you choose to pay the printer, then it's because the printer is providing a valuable service.
Stallman would presumably say that the wrong is not that you have to pay to get a copy of the music, but that (depending on the license the printer grants) you're forbidden from sharing the music.
As with software, it's very difficult to get the law changed, and it's hard to know what the overall effect on society a given change would have.
If you want to be free to copy or perform music or software, then the practical solution is the same as with software and books: copy a 19th century score yourself (or compose music yourself), make it freely available to others, and encourage others to do the same. If Project Gutenberg and similar projects are practical, then musical equivalents should be all the more so.