The .280 is still alive and there are less new rifles in that chambering than the 7mm-08, but yes, the Creedmoor is taking away market share that would have been occupied by the 7mm-08 or .243 in years past. There may be slightly fewer ammo offerings in 7mm-08 in years to come, but there are still a lot of existing rifles in that chambering.
For my money, I like it better than the Creedmoor or the .308 as a hunting round, but it's really not much different overall in that role. I shoot them all.
