Ask Mozart.
The way you asked your question is biased so any response you get you contrary to your idea is most likely going to be dismissed. If you can avoid that, I have some answers.
1.) No instrument has a set role. It is up to the creativity of the artist to find new ways to use something. The role of the bass is whatever the player wants it to be.
2.) Playing more notes is exciting. Playing less notes is boring. For all the yammering TBers do about "the pocket" the truth is no one really likes boring bass players that play less. Even old school guys like Duck Dunn and James Jamerson played more than on-beat root quarter notes. There is a point of diminishing returns for playing too much, but more is more fun.
3.) Its a simple matter of what I think of as "leveling." I'm a RPG nut, which are full of skill trees. To move from one level of the skill tree to another, you have to meet the prerequisites. If a bass player can shred, its given that he\she can just play a back beat. Mike Manring, Victor Wooten, Les Claypool, Nick Schendzielos, Jaco, Stanley Clarke, Ryan Martinie, etc, etc, etc can plan anything they want. They OWN their instrument. Playing whole notes at 90bpm is a waste of their enormous talents.
4.) No one talks about the "pocket" players because no one cares. I don't know anyone that says Michael Anthony or Nikki Sixx are awesome bass players. People may like them because of their bands or their personalities, but they play forgettable lines. They are co-stars in someone else's movie; I can't dig that. Steve Harris IS Iron Maiden. He doesn't need to shred solos, but his playing is what drives their songs. Geezer Butler is Tony Iommi's equal, not his rhythm section.
5.) If you think less is more, try listen to SunnO))) or some other drone band. That stuff is boring AF.
6.) Some people have a little trouble with this: James Jamerson has been dead for 33 years. The Beatles were a big deal 50 years ago and Paul McCartney hasn't been a relevant musical force since the 80s. That stuff is old man. They played in a style that doesn't really exist anymore. Music has become more complex, as has the playing, to a point where even Rush and Yes are considered a little quaint. As the complexity of the music increases, by necessity, so does the playing of the bassist. If you are happy with old music that there will never be more of, have at it; whatever makes you happy. However, don't be surprised when obsolete playing paradigms aren't enthusiastically supported.