The last numbers I saw were from 2018. 30-06 and 270 had both fallen way out of the top list of cartridges sold. They were lumped together along with all the rest in the "Other" category. Some new rifles being introduced aren't even offered in 30-06 or 270 any longer. There are still a butt load of rifles out there in those cartridges but the trend is toward shorter versions. And I've moved in that direction.
I started hunting in the 1970's with a 30-06 and used it almost exclusively for over 40 years. I tried 280, 338-06, 35 Whelen, 7mm Rem mag, 300 WM, 300 WSM, 30-30, 35 Rem and 45-70 briefly at times, but always came back to 30-06.
I moved to 308 about a dozen years ago and have no regrets. I sold everything else except for one 30-06 with too much history to sell. But I haven't hunted with it in years.
Here is why. In the 2000's a 308 will beat WW-1 or WW-2 era 30-06 performance by a wide margin. With the better handloads I can still beat most typical 30-06 factory loads today. Of course, with hand loads 30-06 will always beat 308. But you reach a point where you have to ask, why? If a 30-06 was enough in the 1960's, 308 beats that today. And 308 has proven to be slightly more accurate with less recoil, and available in lighter, more compact rifles. It's a win-win-win situation.
Then be realistic about your skills. A 308 has enough power to take down an elk at ranges out to 500 yards +. Can you shoot well enough to do that? If not, why do you need a cartridge that will extend that range farther. Sure, some cartridges shoot flatter, but with modern optics and cheap range finders a flat trajectory isn't nearly as important as before.
The trend with most guys now is toward the 308 based cartridges. And in a roundabout way the 6.5CM is a descendant of the 308. In fact, the majority of the most used cartridges today can be considered the descendants of the 7X57 introduced in the 1890's.
The guys who want more performance are moving toward the 300 WM and other newer 30, 7mm, and 6.5mm magnum cartridges. Even though they may not have the word "magnum" on the headstamp. The 30-06 based cartridges are sort of stuck in the middle and being left behind.