I often call myself a fandom Nanna but considering we have Granny and Mum taken care of, perhaps I can self appoint as a fandom Aunty (yes the oddball one but I'll spoil you rotten) for the sake of adding:
Yes to all these wonderful points and also, as long as these stories live on, new people will discover them and be as excited as we were when Good Omens first hooked us and they will seek out all the fics and the art and the blogs.
There will be little resurgences every time something happens to inject new interest in the series.
One of the loveliest things about fandom is that yes, it will eventually contract to a new "normal", however any time something happens- it might be the anniversary of the finale or the release of new bts footage or an interview or anything-even those whose focus is now primarily elsewhere will jump back in and it's honestly like a joyous reunion.
I have fandom friends on here from multiple fandoms and I adore seeing how passionate they are about shows and ships and ppl I don't know anything about but as soon as anything relating to our old fandom pops up, it's like a party on my dash.
And the other thing is, this fandom has taken Good Omens and these characters and through the incredible fanworks and metas, made them into something so much bigger than the source material. I truly believe that because of this, their stories and the choice to continue to engage in new and exciting versions through all the works that will continue to be produced, will mean we are never left wanting for content.
Fandom spans so much more than the show or the original source material, as I think we've seen. So while it may look and feel different after a while, it's not going anywhere 💛