Yes, it's possible that it's the human factor involved in approving new contributors as well as the process of accepting all of the content they receive. Keep in mind that a ton of editorial news content (photos and video) is posted on Gettyimages, which is timely and requires human review. Humans... they're so inefficient!
My search on the contributor forum returned a single chat thread. Here's the text of the original thread:
[REMOVED because the quoted thread was misleading and perhaps outdated]
I saw another thread on PhantomPilots about the stock agency VideoBlocks. I've bought stuff from them before, but haven't contributed anything. I signed an exclusive with Gettyimages for photos and video and haven't worked with VideoBlocks personally. You might earn better commissions through VideoBlocks 'cause I feel like I'm getting jipped by Gettyimages with their low commission rates.
Contributor Portal
Create a thread here on PP about VideoBlocks and see what others have to say.