Bummer, it was probably the most exciting ongoing project related to the Fediverse... With lemm.ee shutting down today and all it's a hard time being optimistic about these platforms

Federation and decentralisation will always hold merit as concepts—however, IMO, the solutions like ActivityPub won't. Scaling is the big issue that most solutions I've seen tend to struggle with. What works with a few million users doesn't necessarily still work acceptably or reliably as you get into larger figures.