At first she was manufactured. She didn't even want to be a singer. But once it was discovered that she wrote beautifully, they decided that Hamasaki Ayumi was to be an artist who wrote her own music. That earned her a bit of influence from the start, straight from her first album.

After that, she gradually gained more and more influence, co-producing music and PVs and such, controlling her image way more than most artists are allowed to, and eventually composing the music to her songs.

Ayu is an artist; she is a creator of concepts and visions. Just because she isn't part of some local indie garage band that got picked up by a major label doesn't mean she's "manufactured" per se.

People are just arrogant and ignorant when it comes to understanding the entertainment industry. Tell your friend he should only talk about things he's educated in.