Ideas don't come from nowhere, they are seeded from other things that have been seen and experienced. On a small network like Nostr it is highly likely that multiple people receive the same seeds and eventually reach similar conclusions.

This morning I was happy to see jb55 post a note mirroring my thoughts on lists of npubs that had recent interaction, which I had posted a few notes in the previous days.

It's probably not coincidence, but an indication of an undercurrent of thought that hasn't yet crystallized, yet exists within the larger conversation.