GNR are not going to give a website with a few thousand readers exclusive content before giving it to, say, Rolling Stone, who has millions of readers.
This forum has over 14,000 members. Of that, 8957 members have 0 posts. Of the 14K members, I would say less than 1000 members are active and keep up with the forums.
I bet there are less than 10,000 active readers of all GNR fan sites combined.
Compare that to Rolling Stone, Billboard.com, Guitar World, Classic Rock, etc who have millions of readers.
Stop being naive.