Copyright stemmed from the invention of printing--although as is often the case, the law trailed the technology. In the prior world where books had to be copied by hand and performances couldn't be fixed in a medium, there was no real need for copyright. What would prevent that prior world from existing today is that technology has advanced to a level that many things can be replicated with essentially zero cost or effort.

I agree with your point with respect to open source code however. Open source software licensing, especially permissive licenses, is largely divorced from attribution--especially in the context of those actually using the software.