If any formulaic approach ever worked, then everyone would be writing hits all the time.
It’s an ok questions, I suppose, but there is no answer.
I agree with you that there is no one answer, Mike. There are plenty of theories and lots of science about songwriting, but their application doesn't ensure an interesting song, much less a hit. On the other hand, AI will write a hit song soon, if it hasn't already. I'd like to think I won't like it, but I might. Didn't think I'd ever appreciate vocaloids either...