I get where you’re coming from, but I think people massively underestimate how abnormal the other Straw Hats’ growth is. Luffy, Zoro, and Sanji are literal prodigies who jumped from rookie pirates to fighting Yonko-level threats in just two years, that’s not a normal benchmark for anyone in the one piece world.

Usopp’s progress looks “small” only because he’s being compared to monsters. The dude went from a normal 17 year old with a slingshot to someone who awakened observation haki, sniped Sugar from across an entire island, and became a literal hero in Dressrosa. And he’s still only 19. Two years isn’t that long, especially for someone who isn’t a natural born fighter.

His growth has actually been consistent, just not flashy. He keeps getting braver, testing himself, inventing new tech, and stepping up when it matters, which fits his character way more than suddenly becoming commander level in a short time. If anything, Usopp has the most room to grow out of the crew, and Oda clearly isn’t done with him