There’s been a LOT of hype going all the way back to the late Victorian era in rifles. Charles Newton, Charles Ross, were all proponents of small bullets at high velocity in the early 1900s. And they work, except when they don’t. Then the heavy and slow comes to the front again. It isn’t just marketing, either. There’s a lot of buzz about the gee-whiz power, low recoil of the latest hot cartridge. Then someone uses it on a big bear or a big cat.
You’re right in that a lot of hunters aren’t very good shots particularly at longer ranges. Hunter education is a key, but there’s a lot of resistance because so many see limits as a limit on their “manliness”. (I know a bunch of guys at my club were embarrassed when I beat them in Highpower rifle.)
All of this isn’t new to those of us who’ve been around a while. I even had the test lab Manager at Remington say to me “there’s something magical about the 7mm bore”. This was in 1980. And I remember all the hype about the 264 Win Mag, the 7mm Mag, the Weatherby line, the 308 Norma, et al in the 1960s. Most of us old fuddies have seen this s**t before.