I think you are misreading the point that the original poster in that thread was trying to make. That the number of active apache contributors is in a downward spiral and what to do about that. If I do as you suggest some quick measurements on similar projects it does seem the poster was correct and other projects see a different (active) committers pattern. It is hard to do statistics on openoffice since they are still stuck with subversion, but luckily libreoffice has a converted git branch for the project to easily cherrypick.
Take the commits, committers and active committers, who made at least 10 commits in the last 4 months, and compare them with the numbers of the 4 months before that (just the core code, no website edits):
Sep/Dec 2012 aoo 562 commits, 29 committers, 14 active. calligra 770 commits, 49 committers, 13 active. libreoffice 6541 commits, 157 committers, 59 active.
Jan/Apr 2013 aoo 576 commits, 17 committers, 9 active. calligra 1013 commits, 51 committers, 18 active. libreoffice 7631 commits, 223 committers, 69 active.Above using
git://anongit.freedesktop.org/libreoffice/coremaster and aoo branches, and
git://anongit.kde.org/calligramaster branch. LWN has some code to produce much better stats from git repos if you like:
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds