Some of these duplicate communities are just placeholders. But sometimes, the differences are obvious, where one community Is populated by jerks or modded by power-trippers.
Over time, the more popular community will become clear by the number of subscribers. (Or the real, topical one will give itself a different name to avoid confusion with the jerks).
Yup. Money was never a problem for D&D. HBO was willing to give them all the time and money they needed. That is a very rare thing in entertainment.