To understand the GNU FDL it is helpful to think on a printed software handbook. Think on a title page of a software handbook. You cannot list lots of authors there. Therefore the five main authors rule for the title page. I cannot see what the equivalent of the title page in Wikipedia would be.
Wikipedia/WMF is constantly (in bad faith) denying that the version history is the section history of the GNU FDL. If you are changing a work you are obliged according the license to update the section history. The section history is the only place where each author gets attribution. Think again on a software handbook with single contributions of a lot of authors. The section history says * article U (c) by V * article W (c) by W and so on.
Each Wikipedian has nothing to do with updating the section history. But an update is necessary according the license. The logical conclusion must be that the version history is the section history and that the "Gentlemen agreement" for online users is invalid because each re-use has to copy the section history i.e. the version history. For verbatim copying this is the consequence of the fact that the section history is part of the document. For modifications see the GNU FDL:
"Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence."
For a comprehensive interpretation of the GNU FDL in German see http://de.wikipedia.org/wiki/Benutzer:Historiograf/GNU_FDL_Highway_to_Hell_-...
Klaus Graf