Should have placed some "quotes" around that or some other signifier...as a revolver man who often carries a 640 pro, I hardly think .38/.357 is dying. But it seems to sell fairly poorly at Wally World compared to .40 in my neck of the woods.
When I see gun articles talk about "cheap .38 target ammo" I feel like they are talking about a past now gone.
.40 is popular enough around here that the local convience store used to stock it, along with .30-30, .243, .308 and .30-06.
NC shooters seem fond of .40, and .357Sig to a lesser extent. I think .40 is still issued by a lot of LE here.