I suppose it's link to Ezra day. I think one should always be rather suspicious of market-based arguments to explain the content of the product we call "news." MSNBC is a small part of a much larger organization whose interests are somewhat broader than just advertising revenue. Ditto ABC News, the Washington Post, CNN, etc. Even to the extent that MSNBC head honchos are trying to maximize advertising revenue and viewers of the right demographics, it doesn't mean they have any idea what they're doing. Their target audience for a long time was "moderate Republicans," believing CNN was "left," Fox was "right," and their sweet spot were people who voted Republican but weren't total Bush cultists. In 2004 there were about 5 of these people so I don't think this was a particular smart strategy. And despite Olbermann's long success, it took them forever to do what any intelligent programmer would do and pair him with companion programming that would appeal to the same viewers. How long did they keep Tucker's zero-rated show on? Clearly they had other motives.
Also journalism itself is hamstrung by weird professional codes and cultural practices for better or for worse. While they may not always be lived up to, they do impact how news is covered even if there are more appealing ways to do it.
Obviously the "market" matters, but the financial incentives must be thought about a bit more broadly.
