That seems like quite a high bar, to the extent that I'm not sure we could ever credit anyone with creating a pop song if it applies. Everyone seems comfortable crediting Lennon and McCartney with their various Beatles songs, for example, but were they doing all the things you describe? Did they do more to create those songs than, say, Taylor Swift does for hers? It's not obvious to me that it's the case.
Yes, they did. George Martin was an arranger, not a co-writer. Max Martin is a co-writer.
If you gave Lennon and McCartney a couple of guitars, a few days of studio time, a good mood, and no other help you'd probably get a hit. Or at least an interesting song.
If you gave Taylor Swift the same you'd get a demo, maybe. You might get an unassisted hit, but the odds are much lower.
Charli XCX - even more so. Give her a laptop and microphone and some plugins and no producer, and I doubt you'd get much.
Not to say that what she and Dua Lipa do is easy. But they're fundamentally performers and brands for a music production operation.
Creative agency isn't a binary. It's on a spectrum. Some people have very little. Some have a lot. Some have taste that defines the product, even though they're mostly curating other people's work.
Michael Jackson was notorious for this. He was a phenomenal dancer, an ok vocalist, not much of a practical musician. But he had a strong sense of what he wanted, and he had a theatricality that pulled the whole thing together.
Charli XCX is a version of that. I don't think her appeal is as strong or as universal, and I doubt she has as much agency as Jackson did. But it's the same idea - shape, curate, perform.
Yes, it's absolutely the case for Lennon and McCartney, since they didn't give rough ideas to George Martin to fill in; they specifically wrote the exact melodies for half the instruments involved and exactly how to play them.
You could argue that Harrison and Starr always deserved some of the writing credit, since they often determined their parts, and I wouldn't actually disagree with that -- though Lennon and McCartney were kinda control freaks, so I'm not sure how much leeway was actually given. When they started bringing in extra instruments, again, there is arguably some extra credit to be given to Martin and others, but Lennon and McCartney were still strongly directing what was to be played.
For what it's worth -- and this is going to get me hated even more than my popstar-skepticism -- I don't really like the Beatles that much. But it's transparent that they did more than Taylor Swift because they were specifically and precisely writing the melodies for the instruments being played.
