The 6.5 Creedmoor is doing a pretty respectable job of sweeping aside a wide range of short action and small bore low power cartridges. From a big game hunting utility perspective it's got the .243, .257 Roberts, .25-06, .260 and .270 solidly beat. The 7mm-08, 7x57 and .280 retain a hair of additional utility, but only with 175s in a suitably twisted barrel, so they're nearly sunk too. The .308 and .30-06 still have some utility for longer bore life, and as crossover hoofed animal/bear rounds. But it's looking more and more like the .308 will be autloader only and the .30-06 will get what it deserves, which is obscurity. We're not there yet but getting there.
The rounds that are safe from the 6.5CM are the .280 AI and 7mm magnums. It really can't come close to the performance, although the 6.5 PRC and the 6.5 WSM if ever adequately standardized are possible competitors.
On the dangerous game crossover end the medium bore magnums continue to dominate as they should.
While I agree with some of what you wrote, I disagree with some as well.
For starters, the 6.5 Creedmore falls short to a well loaded .270 Win. Daughter’s l.270 load for a 150g ABLR beats Hornady’s 143g ELD-X for the 6.5CM by 6” drop, 150fps, 265fpe and 1/2” drift at 500.
As to the ..30-06, it will be around and popular for decades to come – for many good reasons.
{Edit to add]
Made a mistake in my original calculations and used 7500ft altitude for the .270 instead of 500. (The 6.5 CM calcs were at 500.) The numbers have been corrected. Original numbers were "9” drop, 300fps, 500fpe and 4-1/2” drift".
More importantly for our purposes, at 7000ft altitude and above, and while the 6.5 has a miniscule advantage in drift out to 300 yards (after which the .270 wins), the .270 load beats it handily in all other categories put to 1000 yards, the limit of my calculations.
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