Out of the 49 arcs of the story, the only times Sakura was truly useful, was in the war arc, and the Kazekage rescue mission. the remaining of the arcs have her either being a hindrance to others or doing idiotic things for the sake of the plot.

For example, the kage submit arc.

Sakura brought the rest of the rookie 12 to stop Sasuke, whether that be capture or death. This could have been a great turning point in her character, only for her to poison her comrades to confront Sasuke herself. And instead of stopping him, she ended up hesitating and then needed to be saved by Naruto.

That is sad compared to the other 3 main characters that influenced the story.

Sasuke- a reincarnation of a demi-god, Wants to avenge his clan by any means necessary, The last of his bloodline at the end of the story

Kakashi- son of the white fang, Teammate/student to Minato and Obito, Actions led to his remaining teammate dying, and unknowingly led Obito down a dark path,

Naruto- being born

During the entire story, there is nothing Sakura has done for her character to be irreplaceable from either Tsunade/Shizune or a random medic ninja.