At its most basic levels, with detail left to illustrate the point but not define it, what we are talking about is "the social creation of reality," as I studied in college sociology. Different historical ages, and different political eras both embody and create a dominant view of the world. Hence, Renaissance Italy was different from Stalinist Russia. In a sense, the dominant view establishes a paradigm for thought, one believed to be most advantageous to its time. The Enlightenment, for example, untethered scientific inquiry from religious stricture, as confounded Galileo.
Ultimately, the utility of a given mode of thought determines its survival as a paradigm. In this regard, beyond indisputable "sheer" facts, the orientation of the media in America now, in my opinion, is most conducive to the fulfillment of the promise of our liberal democracy, as founded and as extrapolated to its best.