The GPM team was hugely passionate about music and curating a good experience for users, but YT leadership just wanted us to "reuse existing video architecture" to the Nth degree when we merged into the YT org.
After literally years of negotiations you got... what YTM is. Many of the original GPM team members left before the transition was fully underway because they saw the writing on the wall and wanted no part of it. I really wish I had done the same.