Who and what to blame?

The "ceiling effect" in profitability of physical mainstream media products makes sense since (1) there are limits to the common denominator formula (2) physical markets tend to be much smaller than online markets. 

But these limitations don't apply to online stores. On the internet, while online stores can still carry "mainstream" products to aim at the common denominator audiences, the online environment eliminates the two possible ceiling effects with 1) low to zero cost for storage and distribution and 2) elimination of geographic markets. In other words, online media stores have the best of both worlds in terms of offering endless content amd having countless potential consumers, both of which are reason enough for the triumph of long tail effects.

I think the competition media companies in the physical world whines about (for the lack of a better expression)  is not necessarily one of "online vs. traditional" per se - but one of "who is better at satisfying the needs, or even quirks, of their customers/audiences?"  The news industry faces the same problem.

Legacy media industries, arguably, never took the time to fully understand consumers/audiences in their geographic region to cultivate loyalty and rapport, and to improve customer/audience satisfaction. For example, Borders in Brooklyn, NY should not carry the same items as Borders in Lubbock, TX, but chances are they probably did carry identical things for the reasons Chris Anderson detailed, and I think this is really a shame because "localness" is one of those attributes that online stores can never take away from physical stores. 

In sum, market negligence in the physical world is a worse enemy than the "traditional vs. digital" debate accounts for. In other words, in order to stay competitive in the 21st century, unless physical stores can carry as much content choices as online stores do to entice their customers/audiences, they better figure out what their unique attributes are -- stop talking in terms of "what I can offer you" and start elaborating on "how I can meet your X and Y needs in ways that the online stores cannot."