I think things could get a lot more interesting if other software that is more like classic bulletin boards and forums would implement ActivityPub. I mean, such online forums are still able to thrive in their respective niches. If such forums would become compatible with Lemmy, Kbin or Friendica, it could bring a whole new dynamic to this part of the Fediverse. At the same time, it would help these niche forums get more attention (even though I’m not sure if all or even most of them are interested in that).