Enjoy the Aventine; don't enjoy Captain Ezri. The very idea that she's a Captain before literally every other character in all of the 24th century just chaps my ass.
You're forgetting Kira Nerys (promoted to captain in 2376), Chakotay (promoted to captain in 2378), and Will Riker (promoted to captain in 2379). Not to mention Elizabeth Shelby, Kat Mueller, and Sonya Gomez. A lot of 24th-century series-regular characters (counting Gomez as the SCE lead) reached captain's rank before Ezri was promoted in 2381.
It's not as if every character is even pursuing captaincy in the first place. Militaries don't work that way. The higher the rank, the fewer people ever reach it. And ship command is just one specialty. The majority of people in any naval service go through their entire careers without getting ships to command, because quite a lot of them aren't trying to.