To some extent, I think the problem is feedback. We have a section in the forums for people to post about their own worlds and settings, but the number of responses is low. There's surprisingly little response to Guild Companion articles, which include Peter Mork writing about his own setting.
I'm not sure of the cause. It's got to be at least partly that we tend to make our own settings, and therefore don't need anyone else's. But I think more engagement would encourage more content. Certainly the RMU forums shows that there are enough people with opinions on the forum to maintain good discussions.
None of which is intended to discourage you from contributing your own work, whether on the forums, in the Guild Companion, or in a blog... I do suggest that if you use a blog, you also post about it on the forums, if only to drive traffic.