Why is open source not meaningful? Open source software has proven to be very competitive and often superior to closed source, protected software. People even make money writing open source software.
Not many make money authoring books, despite copyright protections. Same goes for musicians and artists. By making money I mean not needing another job to pay the rent.
Open source software has indeed been successful in the presence of closed source software.
However this is not true for films or books. Thus the fact that OSS is successful today is not evidence that books and films will be successful without copyright protection. It’s not evidence they won’t either. Thus it is not a meaningful comparison.
The economics of open source software and fiction books or film are wildly different.