One needs to remember that not all shooters, or rather, gun owners, know how to take care of their guns. The AR is still a mystery for many of their owners.
For example, I am sure we have all seen the video of the guy who has an ammo issue with his AR but he keeps chambering rounds, bumping the forward assist button and getting clicking sounds after pressing the trigger. He does this until the gun blows up.
Then there was the time when I when to a local public range (I think that was the last time I ever went to a public range,) a few years back. Some guy was messing with the trigger of his AR after removing the upper. He kept pressing the trigger and letting the hammer hit the lower's front end. I cringed every time he did that and finally I walked over and gently informed him that was not a good thing to do, he should put something between the hammer and the lower to catch the hammer. He gave me "the look" and I just apologized for disturbing him and left.
I have seen too many people buy an AR, and the very cheapest ammo they can find and then load up mags and just empty the magazines in the general direction of the target. Most of the rifles I saw were simply not lubed.
We all know a DI AR will run forever, provided it's wet. (I do grease myself, but I have oil just in case a quick squirt may be needed. Anything is better than running dry.)
So, I have no difficulty in believing that CFAR sees abused ARs.
I would think however, that anyone here would have no problems running their DI ARs as long as they need to run.
