I think the creedmoor is popular in some ways bc Hornady took an approach from the tech industry.
The difference between Apple and Samsung smartphones when they were first introduced 10 yrs ago? Apple made sure the ecosystem was in place. A cartridge can be wonderful but it needs more than just a cartridge. It needs gun makers and ammo makers to jump in with both feet as well. Hornady made ammo that worked well with the guns that it made sure were made by manufacturers. Buy a gun, ammo is available, now just go shoot. You have lots of choices for guns and ammo.
Apple made sure that the App Store had tons of apps - the Google Play store took years to catch up, and Apple pushed the ease of use in getting the most out of your phone by pushing the App Store angle. Sure, the iPhone was first, but the hardware was easy to replicate. The ecosystem was not easy to replicate quickly. Remember 'there's an app for that'? Now see the ecosystem for the 260 Rem as a counter example.
Sure, marketing is huge as well and that angle has been a huge push for the creedmoor, but marketing without a good cartridge and a thriving ecosystem is talk more than anything. The tech industry is all about the ecosystem, and Hornady took a page out of their book.