I don't think anyone in the media wants to embarrass themselves by predicting that our offense will be good, and then have it turn out that we can only score 15-20 points a game (like the last 2 years).
Also, if you were an outsider writing an article about our offense, you don't really have a solid basis that our offense will be good this year. They haven't proven anything. It's easy for us to sip (or chug) the kool-aid, but writers don't have that luxury, unless they're talking about Missouri (apparently).
Also, most writers and "experts" are just terrible, and make only a cursory glance at the roster, read a few local newspaper articles, and then make their "predictions." It's the kind of malaise that the evil possess and the sane lament.