The greatest damage the 6.5 Creedmoor has done to the .243 is to offer a common, widely available alternative to it.
One that offers more power than a .243 for larger medium game like muleys and bear and as necessary for an occasional elk if desired.
Most .243 use I have experienced is in the form of a lightweight deer rifle for youths and wives. I always thought it was a little light for big black bear and mulies at long range.
The competitors to fill that notch have included the 6 mm Remington, .257 Roberts, 6.5x55, .260 Remington, 7mm-08 and for me at least, the .300 Savage. None of these, in my opinion, have been well supported with rifles appropriate for that use or had commonly available ammunition. The .260 Remington is, or my uses as good or better than the Creedmor but there aren't many and ammo is made of unobtanium.
I bought a 6.5 Creedmoor in a Kimber Hunter when they first came out for under $700. Ammo is available in lower priced, good quality loads like American Whitetail.
My sporterized 6.5x55 1894 Carbine doesn't get near as much use now as it used to.
