Even if this were true they pay for themselves in 1.5 days of being online. Some of the biggest sites online right now are nothing but links to other blog posts, how is doing it on a smaller scale than say technorati grounds for bannishment? That being said, no I don't pull in duplicate posts x 50k.
This is very true, especially the entertainment blogs, it seems like they have a few stories that seems to be shared by different ones. And I don't see them being penalized. Though I don't know how much money they make, I bet it isn't bad for the effort they put in.