I think one could make a case that virtually any handgun cartridge is "dead" based on another doing all, and then some, for which the "dead" one is capable. Remember the .32 Long has a well-deserved reputation as an inherently accurate cartridge and that's contributed to it's longevity I'd imagine.
I think asking if a cartridge is dead or dying is an interesting exercise though. Like so many previous posts; as long as I'm involved in shooting sports it will be alive around these parts.
From pre-Model 30s, Regulation Police, a Model 30-1, and some assorted Colts, I truly enjoy shooting the .32 S&W Long. It's perfect to introduce more petite shooters to centerfire handguns, a pleasure to reload stretching powder a long way, and bullets are reasonably purchased on-line.
Having never served in law enforcement it is admittedly difficult to imagine hitting the mean streets with a Regulation Police in .32 S&W Long in your holster. I seem to prefer larger handguns that retain their weapon status even when they're empty. Apparently the .32 S&W Long was considered quite adequate for police work once-upon-a-time.
I do find the relative size of my .32 revolvers easy to carry as a ranch "walkin' around gun" and have used the cartridge, on occasion, to dispatch wounded feral hogs and a few whitetail deer. It's dandy on cottontail rabbits too.
A brace of .32 S&W Longs from the inventory.