Why are health and nutrition, and music theory not in beta yet?
Health and Nutrition and Music Theory are not in beta yet because going by number of founders as a way to gauge whether or not a subject can be released is not a good strategy to use.
All the subjects that were promoted to beta after at least 8 people signed up as founders eventually graduated from beta because the community stepped up and did what the founders were supposed to do.
Simply put, none of the subjects that had at least 8 founders actually benefited from input from all the founders. In fact, a lot of subjects only saw contributions from 2 or 3 founders over the period in which the subject was in beta.
A lot of people signed up to be founders without realizing that their contribution will be needed in order for the subject to graduate.
US History is a perfect example of that. This subject was one of the first to be promoted to beta status, I think almost 6 months ago, yet it's as far from graduating as it was a week after it was launched.
World History, Environmental Science, and Psychology are pretty much in the same position. Astrophysics is not doing that well either.
So, to sum this up, the number of founders will no longer be a criterion for promoting a subject to beta status. The team is working on figuring out other criteria that can be used to gauge whether or not a subject should go in beta.
Until that happens, subjects will no longer be promoted to beta.