I agree with you that the writing is often not great.

On the other hand, I see a disproportionate number of "Top X reasons"-like posts hitting digg and delicious/popular which leads me to believe that lists resonate well with readers. I'm not a blogger or link-baiter, but I'd prefer to write a mediocre article which is read thousands of times via prominence on social media sites versus a 'well-written' article with no numbers/lists that no one reads.

It seems like consumers of blogs and social media like lists, so bloggers logically satisfy that need.