bigbadron:
GMs were informed of the option, so the "far larger number of GMs who are simply unaware that such facilities exist" would actually be far less than you suspect.
Basically if a GM wanted to change his game to an open forum, he was told that it would stop him advertising in W-P, but we could post a link for him in Game Systems.
Perhaps, then, the totally unaware GMs is less than I thought - assuming others have been alerted to the options since 2012.
However, your second paragraph suggests that perhaps rather than being uninterested, they simply chose the devil they knew.
I don't understand why the resource 'games' can't be advertised both ways - why the need to choose? If they're producing a resource that benefits the community, can't they be rewarded with a little extra advertising?