I fear they are gone for quite some time.
When Mona was here around (she isn't with PTC anymore) she offered to post any sheets from the ressource pages which would be requested and did so for some ebooks, etc. But of course those posts are buried under a pile of later posts and hard to find.
Now the forum is flooded with a myriad of documents in varying quality - all of them only in Prime format, as you noted. The more there are, the more confusing is all. The various index/content documents help but the medium her is not suitable to build a permanent ressource center which should be clear, easy to navigate and searchable. And putting every sigle file on its own page isn't really the way it should be presented.
I don't understand why a more or less static and permanent content is poured in a medium which is made for dynamic, mostly volatile content. So they need artificially created anchors like the "Featured Documents" region to save those file from going under completely - thats a bit amatuerish. Wrong tool for the task.
I heard from PTC that the reason this is done that way is, because the community is much more frequented than the PTC homepage. If can easily image that, given that the PTC page is quite baffling and hard to navigate.
The other option probably was to make the PTC page clear and user friendly, but was not considered because ....?
