Currently, if mod_muc_mam isn't loaded (whether directly or undirectly through mod_mam), the MUC component won't support stanzaIDs and occupantIDs. But the XEPs don't specify such dependence. The decoupling will allow features like moderation, retraction, replies and reactions to work when MAM is disabled. Moreover, the upcoming GC3 spec will make occupantIDs mandatory, but it will probably keep MAM optional. So, Prosody will eventually have to decouple the features anyway.