One could understand why not writing your own songs seems like a bad thing especially when somebody else also needs credit. It would be even worse if it’s plagiarism because that could be infringing on somebody’s copyright. If people grew stricter on musical plagiarism, then not writing your own songs is now optional especially if it’s derived from the public domain.
That would force songwriters, musicians and producers to be more cautious with that they chose. Making a pop album out of the Canterbury Tales seems strange at first but novel and welcome in the anti-plagiarism purge years. They could even give Geoffrey Chaucer a posthumous credit. Folk music’s another example but that’s when the actual authors are anonymous to begin with.
Both of these are public domain, which is something pop musicians will take advantage of to avoid plagiarism in the future.