That's very interesting, and something I never realized, and it is also something I didn't miss. He offered a couple of possible reasons:
But when we ask our readers to follow a technical story—one that we've struggled to make as accessible as possible—they deserve a payoff for investing their time. Speculative theories whose prospects for vindication are remote don't quite deliver.
There's another, more mundane explanation for the dearth of string theory news in Physics Today. Search stories tend to be about one or two papers. In fields where significant individual advances are hard to spot, the expert-written feature article is often the better editorial option.
Both of which I agree on. But this brings out an important observation, especially to the public. Considering how "sexy" and "hot" string theory is that has captured the public's imagination ever since Brian Greene's "The Elegant Universe" aired, the public should now recognize that string theory isn't "big news" in the physics circle. Not only is the percentage of "practitioners" of string theory a small number among practicing physicists, but its impact are currently rather small in the world of physics. The lack of coverage of String Theory in Physics Today isn't the cause, but rather the symptom, of this fact. One also could look at the physics papers published in Science, Nature, and PRL. Now, compare that to, say, topological insulators. Now only is this topic getting widespread coverage in many science magazine, but the impact is also widespread beyond just condensed matter physics. But things like this, which a large percentage of physicists consider to be important, are not sexy subject and do not get media and public attention.
So, in my opinion, Physics Today's coverage of String Theory is just right, and commensurate with the level of impact and validity. If and when it achieves some level of validity and testing, then I'm sure that will change.