I'm not sure what the point of the poster was. You can see the projects with "passing" or better here, and there are over 200: https://bestpractices.coreinfrastructure.org/en/projects?gte...
There are very few projects with gold, sure, but gold is a more recent badge level and it's pretty hard to get. In addition, we've been emphasizing helping projects get the "passing" badge, and we have so far spent less time encouraging projects to work on higher level badges (silver or gold). Most projects working on higher level badges tend to work on them slowly, instead of trying to get it all at once anyway.
I think a more telling chart is the steady increase in the number of participating projects: https://bestpractices.coreinfrastructure.org/en/project_stat...
If you are involved in an open source project, I would encourage you to get a badge. Go here for more: https://bestpractices.coreinfrastructure.org/