I am comforted by the words of Col Cooper, when shown a new product and someone asked him what it was for? "Why, to sell, of course."
Gun companies and ammo manufacturers make new guns/calibers/bullets/etc to sell. There are lots of us who know that our old .30-06, or .30-30, or whatever cartridge will do the job that we need it to do. I don't believe I own a rifle where the cartridge was introduced after 1964. They kill with authority within their limits and I'm perfectly satisfied with their performance.