I see the same thing. A friend frequently recounts his 960 yard antelope, or his 600 yard elk... he also thinks his reloads are going 3800 fps. I asked once, have you ever chronographed those loads? No.
Flip side, two of our hunters in the 3rd elk season showed up with Jarrett and Christenson Arms rifles, lasers, and range cards that had been field tested. In conversation it became apparent they had plenty of experience dealing with wind, and both were quick to say if conditions weren't right, long shots may have to be passed.
Those were the first two hunters I can ever recall in over 30 years of guiding that had real experience with long range, and expressed a willingness to pass on shots they didn't feel confident about.