I think your analysis sounds pretty spot-on, and while I hope really hard that fanart does find a forever home (and I think podfic and other audio, too, has good chances of that), the idea of fandom moving to Discord or Reddit is... completely horrifying to me. Neither of those platforms works for me at *all*, and I don't know how to live my life without being on the pulse of fandom. :| Unfortunately, I think you're right with those being the most likely candidates. Augh.