Good point, and that does happen. Tony Levin gets hired for "his" sound, as does Pino, Flea (when he does side work), and there are others. But that is probably not the typical case. More typically, the bass is supposed to fit in with the drums in the track and fill out the sound -- and not draw too much attention to itself. It also helps if it's easy to record and mix, so that the artist, engineer, producer, etc., can spend time worrying about a bunch of other stuff. As humans, we seem to get used to things and resist change: e.g., not many quarter tone chords in pop music, songs with the same basic chord progressions over and over, same lyric/song themes, same instrumentation, etc... The P bass is just another cog in the wheel of musical conformity that changes glacially. As a human who resists change, I love the P bass sound, and unfortunately, I'm probably not going to reinvent the instrument like Jamerson or Jaco anyway