In the 40 years I've been shooting, I've seen a whole slew of new cartridges hit the market, only to fade into obscurity.
Very few ever seem to gain enough popularity to stay in the game for the long run.
Off the top of my head there's .357 Maximum, .32 H&R Magnum, .327 Federal Magnum, .41 AE, .45 GAP, .50 GI, and those are just some of the handgun chamberings, the list of rifle cartridges is even longer.
Anyone remember the Winchester WSM and WSSM family of cartridges ?
Or the competing Remington Ultra Mags (RUM) ???
If not, you're not alone.
It's really tough to come up with something new and revolutionary, that has staying power in the market, because people like to stick with the old tried & true.
That's why most of the cartridges that remain in popular usage today have been around for close to 80 years or more.
.30-30, .30-06, .45-70, .30 M1 Carbine, .45 ACP, .45 Colt, .38 sp., .32 ACP, .380 ACP, 9mm Parabellum, .357 Mag., .44 sp., .44 Mag, there's nothing new here, and that's the way it shall remain.