I ask myself that exact question sometimes.
It's one of the weaknesses of this post-timeskip, with non-Straw Hat allies taking lots of screentime compared to the Straw Hats not named Luffy, while neglecting their character development.
And what makes things worse is that most of these side characters aren't that interesting, some being even annoying or outright cringeworthy characters such as Oden or Yamato.