That's not a good analogy. Mathematicians are employed a) by universities, so their compensation is their salary (+ tenure) or b) by investment banks, so their compensation is their salary (+ bonus). There're no freelance mathematicians selling directly to the general public.

Sorry, but I don't understand how your comment constitutes an objection to my comment - it's more like sideways. Universities don't receive copyrights on theorems either. This proves that copyright isn't a necessary condition for the creation of publicly beneficial intellectual property. Society can create mechanisms to compensate creators by other means: make a university-like institution for musicians, and you'll be OK.

It sounds like you're advocating musicians being salaried employees of record labels.

Sorry again, but I can't parse your comments at all. If we abolish copyright, do you think record labels will continue to exist in their present form?

They are usually teaching and doing research for a school something that is not available for all chosen careers

The teaching option is certainly available for arts and music, I'd guess moreso than for mathematics.

You'd guess wrong -- there is an over supply of art teachers, and under supply of math teachers. If you are in math, you can get a job teaching. If you are in art, you probably can't get a job teaching [art].

This is probably a strong indication we have an oversupply of artists!

I was talking about absolute numbers (sorry for not making that clearer), so your assessment is correct without contradicting mine. The oversupply of arts teachers probably consists of ambitious people who hope copyright will make them rich. Abolish copyright and the teacher/student ratio will likely drop to the math level.

Most likely because the barriers to entry is lower than in mathematics. Everyone and his brother think they are "artists".