Popular Photography, Science, Psychology, Mechanics, etc. have always covered what is... popular. I don't feel these magazines were ever accurate reflections of the subjects they cover.
I've found them interesting, but even when I was into whatever it was that one of these magazines covered, they never really did it in a way that I found useful. They were good for learning what is going on, contain some "how-tos," but rarely helped with what I was doing - even if I was doing exactly what they covered. At least Reader's Digest is "up front" with what it is.
When I was about 14 I found some very old Popular Mechanics from before my time. I remember seeing "plans" to build an hover-craft (and of course wanted one). It was popular subject at the time of publication, but few actually wanted to build one. At the time of these publications, many fathers built their children go-carts with old lawn-mower engines, but through three years of this subscription, none of these old issues even mentioned that.
I'm also reminded of a mid-80s Popular Electronics that had plans to use a VCR camera to build a picture phone, as that subject was all the rage at the time.