partyboy6686
Expert
I don't see it disappearing, but for the average person, it costs as much as 45 and they're just not "feeling" it like they used to. 40 solved a problem for Police and USPSA. It gives the police the "right" balance of power, and with the Major floor at 165, it gives USPSA shooters a major caliber gun that holds more boolits than the 45.
As mentioned above, the gun world has fads, and fads are mainly driven by noobies. When they see the guys with the beards and tatts (as Kirk put it) posting videos saying "40 sucks," it has an effect on people.
As Twangbanger said it is a very popular caliber in USPSA competition shooting. I exclusively use 40cal for USPSA. It is just as cheap as 9mm to reload and I can make major power factor with it.