I see it as becoming a back burner ctg in a few years, kind of how .45acp was in the mid to late 90s. As long as Glock is churning out pistols in .357Sig and .45GAP, they'll also be joined by the dozens of companies making .40 S&W pistols. I expect in a couple decades the ammo will cost more than .45ACP as there won't be ammo made as "over-runs", aka: Gov't Surplus.
I don't own and never will own a .40 pistol. It was a poor answer to a dumb question. 9mm or .45 are the only choices needed for modern Cop & Soldier work. I happen to like both
Fact:
if .45GAP were offered at the end of the 80s there NEVER would have been demand for .40S&W
extra Fact: .357Sig is a darn fine cartridge that is prohibitively expensive due to economies of scale. If the military had switched to this cartridge instead of 9mm (impossible I know) we'd see more LEO agencies using it, and plentiful ammo would be priced accordingly... Just my $.02