I'm a fan of the 9mm in snub revolvers but I can tell you that it does not equal, nor exceed, the ballistic performance of the .357 mag out of any length barrel with equivalent bullet weights.
The 9mm excels in snubbies because the performance falls between .38spl +P and .357mag with substantially less recoil and muzzle blast than the .357.
And the popularity of the 9mm is due to cost, availability, light recoil, and size, which allows for greater capacity while still giving acceptable terminal performance with modern expanding projectiles, and again, cost, cost , cost, because everybody, and every agency, is on a budget. All of that is a direct result of the military adopting it as their standard and the military went with it because of NATO, cost, and weight, not because of performance.
And, most people that carry guns professionally have little say in what they are issued, they have to work with what they're given.