It's because no security or government forces have adopted it. Look at the popular cartridges today, they're all in use by government or law enforcement. 38, 357, 9mm, 40, 45, 357 sig. There's only a handful of people who use cartridges like 38 super, 45 super, 32acp, 32 mag etc, and they don't create the demand needed to ramp up ammo production which in turn keeps prices on that ammo high.
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