It’s about the money! I know all the musicians who played, and arranged, the great singer songwriter hits find the concept annoying and many swear the named artists agreed it was nonsense.
It’s no accident that the longest lasting bands tend to have fairly egalitarian distribution of royalties. In a creative collaboration it is often very difficult to know who really contributed. As an example, and please don’t imagine I’m a Beatles fan but I watched the loonnnnnnnng documentary when it came out as I had Covid and was horizontal and it passed the time, but the song they kind of wrote in it, Come together I think, you could hear a motif played hesitantly earlier by I think George emerge as the big contribution by John or Paul a good bit later. When bands don’t have to stress who actually wrote but instead are all hands in, all get paid, everyone contributes to the vibe, they have a better vibe and last longer. Because it is really genuinely difficult to untangle who really contributed and who should really get credit.
The studio crews of the 70s were greats of course and made some of your favourite music if you like stuff from then.
