AmaroK is a music manager. Windows Media Player is a music manager. But not iTunes.
The only thing I've been missing on OS X is a good music manager that can take care of the gigabytes of MP3s I have lying around on my disk.
It not striking your fancy is not the same thing as it not being a music manager. It is one, it is even the most popular one, regardless of your personal opinion of how good it is.
If I wanted a big list of songs, I could put all my MP3s in a single folder and use VLC to play them. Search is easy with Spotlight. This is hardly "organization". For someone who can't purchase music from iTMS, what's the point of iTunes, then?
WMP, AmaroK and even WinAmp allow me to do much more with my music, and they aren't 80megs in size.
I admit, my usage isn't particularly sophisticated. I typically use the browser (with genre, artist and album columns) to drill down to music, or the full text search to quickly dig out something specific. I also have quite a few manual and smart playlists.