The biggest plagiarism scandal in music would cause people expect a lot more from professionals. The criteria changes, so it’s not enough to write your own songs but also come up with your own ideas or otherwise you’d be using the public domain a lot to avoid plagiarising somebody’s copyright.
Musicians accused of plagiarism would be seen as unimaginative, untalented and worse, good for nothing. One might observe a double standard especially when musicians and songwriters that use the public domain are seen as creative and highly talented but legally because they’re not plagiarising those that still have a copyright.
Once the public finds out about the dubious relationship between Ysan Roche (an underground musician) and Lady Gaga (a mainstream one), people will chastise the latter. Ironically along with the heavy reliance on the public domain would prove rockists right about the music industry.