Not precisely true, or so Dr. Weevil says at some length.
What exactly is a 'fact', and where do newspapers get theirs? ...What exactly is it that newspapers can do that bloggers can't?
Here's one big thing that newspapers could do but don't: Compare multiple versions of the same story from different sources. Point out the differences. Find patterns.
Blogging was inevitable once the technology to do so became inexpensive enough.