But...look at the shear number of bolts in sandstone in Utah, the U.S. sandstone belt (Arkansas, Illinois, Kentucky, West Virginia), Arizona, New Mexico, Nevada (1000's in Red Rocks) and, around the world (Australia comes to mind) then consider how many rock climbers sport climb on these anchors, every day, over and over again. When was the last time you heard of a bolt failure?
Now, you don't need to review many years of ANAM to see how often "natural" anchors fail at least for climbers, and, they fail fairly regularly (or the rigging from the anchor) in canyons.
I'm not saying just blindly trusty bolts, but, they are pretty reasonable anchor choices. And, had that anchor not been chopped in this canyon...well...its location alone seemed to be a reasonable solution on a number of fronts.
Yeah, be prudent and consider reasonable anchor choices...especially given how anchor location can contribute to degradation of the resource and safety. Regardless of whether fixed anchors, or, "natural" (or those ugly "unnatural" anchors like rock stacks, deadmen, etc).