Many (but definitely not all) big-name columnists' opinions are in fact "better" than almost everyone in the blogosphere, for a few key reasons:
- They have access to decision-makers
- They have more to lose if they fuck up
But that's exactly the point! They grew so dependent on this 'insider access' that they realistically cannot write anything that goes against the flow. If they do, they'll lose their insider access immediately.
If they ever write something negative then it is usually something that is so big that the respective company they are reporting on can't ignore it anyway; the columnists become a tool of their PR departments working towards defusing the problem by providing a 'balanced' opinion by the columnists.