Of course, it's in practice nearly impossible for me to determine through introspection whether what feels like a "spontaneous" decision on my part is in fact being inspired by some set of external stimuli, and if so which stimuli. And without that data, it's hard to predict the likelihood of other people being similarly inspired.

So I have no business being too surprised if lots of people do think the same thing, either, even if I can't point to an inspirational essay in a community of similar reasoners as a mechanism.

In other words, sometimes collective shifts in attitude take hold in ways that feel entirely spontaneous (and sometimes inexplicably so) to the participants.