I think there's a good chance we'll see the .40 decline in the next decade or two though. People are starting to realize that a 147 grain, or 124 grain +P 9mm will do most anything a .40 can do with less recoil and far less abuse to the gun.
You think the 40 is on it's way out in favor of the 9? I'm trying, but I don't see that. I don't see a hot 9 being anywhere near a 40. My favored load in 9 is a 147+P or +P+, and 180 top end 40, and the way they interact with various media when they hit clearly puts the 40 well above the 9.