Well something like that. They introduce new cartridges to sell new rifles. We had all the options anyone could possibly need more than 50 years ago, there just is no real world advantage to the new rounds. The gun rags pay writers to whip up a lot of hype for some new gadget and build up a fad for those who just have to own the newest, fastest, lightest, shiniest, shortest, longest, biggest, whatever. That does sell guns, ammo, reloading equipment, etc. and that keeps the wheels turning.
The greatest problem for gunmakers is they have to compete in the market with their own products made years ago. Talk about "durable goods", what's more durable than a firearm? There are enough Winchester 94s, Marlin 93s, Mausers, Springfields, even Krags to outfit ever hunter in the U.S. and if they've been at all well cared for they work as well today as anything you can buy brand new. Look at the advances in automobiles, aircraft, and especially electronics compared to firearms. The '98 Mauser came before the model T Ford or the Wright Flyer and there is nothing on the market today that really makes the Mauser obsolete. There have been many improvements and refinements but nothing really earth shaking since smokeless powder and even many of the improvements have been due to improved powders rather than any real innovation in firearms.