I constantly rail about insignificant differences between cartridges, by class, and the cartridge du jour. If one opens the book Cartridges of the World, it is just impossible to find a real niche that some legacy cartridge does not fill. Reminds me of the Cola Wars. The differences between Coke and Pepsi are extremely slight, they are after all, just carbonated flavored sugar water, and yet there are those who are so loyal to the brands, so adamant there are significant and telling differences, that they are rude to others. The same is true for each and every cartridge in the book Cartridges of the World.
The cartridge du jour concept is driven by businesses need to maximize profits now and the fact that the marketplace is populated by people extremely susceptible to suggestion. One good advertising campaign and hoards are running screaming to the local gun store. Of course the 450 Bushmaster does something. It puts a 45 caliber slug in a AR15 action. Will that be enough to create a long and enduring cartridge?, heck if I know. I never predicted the addicting nature of personal electronic devices, in fact, I am the worst person at predicting the future I know. I am totally inept, wrong more than I am right. But I do know that due to the semiconductor, development times have shortened and costs have decreased, so much so, that it is extremely easy and inexpensive to develop a new cartridge and firearm. So businesses can develop a cartridge du jour quickly and cheaply, and throw it at the wall to see if it sticks. If you buy a cartridge du jour, I think the most important thing to do is buy an adequate supply of cartridge cases, for in time, as the round fades away, you won't be able to buy brass. It has taken me years to find new 257 Roberts brass, and that is an excellent, well established cartridge, it has been around forever and written about forever. But it seldom comes in on the tide.