Completely agree with everything you say, especially ramming it down peoples throats on the forum. I think the best way of increasing interest is to just to link to a wiki page when a suitable question is raised.
It may be that people are put off by the techie side of it, which is understandable if they are not that way inclined. Jim expressed an interest in contributing early on, but as he admits himself he's not very good with 'puters.
I think your idea of approaching people individually is a good one. I've contacted two or three for permission to use photos and content, and everyone was only too pleased to help. This including GL who has said we can use content from his site with suitable credits.