I think it works for the population.
The number of forums has to take into account the amount of participation in each for reasonable posting rates and amount of posts. If everything was one forum, you'd post a question and when you came back to check for answers fifteen minutes later it wouldn't even be on the first page of threads.
I've seen new forums just starting out with only their first lot of twenty members, and they have more forums then this...but here we have enough members to spread everything out into the number of fourms we have. I think it's just the right number right now. No one member participates in ALL forums. And we have enough members for that for sure. The way I see it, life is good.