Heretofore there's been a gentleman's agreement about writing credits which benefited the artist, and that's largely been enforced by the reality that artists (and publishers) need writers less than writers need them.
But, what does a pop artist in the 21st century need more than anything in order to succeed? Their image on social media. The underlying threat here is the class issues, and the tactical deployment of the gig economy (song writers driving Ubers) was not accidental.
When the word "exploitation" starts getting thrown around, and comparisons to how black artists were treated in the early years of the music industry start getting made, the pressure on artists and their representation will grow, and the dynamics of the contract process will change. That's what the writers are hoping will happen, anyway.
Songwriting credit is copyright in the music and lyrics of the song. Artist credit is copyright in a specific recording of a song.
So if you write a song which is a great song, and Arianna Grande records a lackluster version which nobody likes that much, but then several other artists pick up on the fact that it's a great song and record their own highly successful versions, then the songwriter would do very well from this, but Arianna Grande wouldn't share in the later success of the cover versions.
If Arianna gets a 30% writers credit just for putting her own 'vibe' on the original recording, then she participates in the upside of the cover versions, even though they might have been successful despite her rather than because of her.
The economic view would be something like:
- There's a pie to be split, often beforehand. Some players are in better negotiating positions than others. Sadly, if you don't know a lot of performers, you'll have a hard time getting a bigger slice from the one that shows up.
- It's not actually relevant who is on the document as a "writer". This is simply a thing to be negotiated over so that the performer is incentivized to do the recording. It's the same thing as putting up sales tax on a purchaser of goods, legally the buyer is paying x% extra, but economically the buyer and the seller actually split the bill according to negotiating power.
- What will happen if it's enshrined that only the person who actually wrote the piece gets his name on it? Well there will be other things to bargain over. For instance, maybe you get your name exclusively on the song, but you put it in a company and the performer gets a piece of the company.