OK, I think I get it. A hostile alien race is planning an imminent attack on Earth. Conventional weapons are useless against them, but owing to their squishy physiology, the meager .380 ACP cartridge is the only thing that can stop them.
Am I close? Because that’s the only reason I can see for the inexplicable shortage of .380. Some folks are stockpiling it like there’s no tomorrow, while those who were late to the party seem to be going into apoplexy over the sudden shortage.
Demand quickly exhausted the supply, and now we’re seeing crap like this: