That's because every billy bob badass thinks he needs a 500 magnum to kill a 150 pound deer.
No doubt, but whether you or I think it's a good move the .357 Mag has been largely replaced. Once upon a time a S&W .357 Mag was the most common cartridge at the range - everyone had at least one revolver so chambered. Nowadays I might not see one, and I don't know a shooter under 30-years old that has one.
.357 Mag revolvers dominated the LEO market. I can't remember the last time a saw a cop carrying one.
