Could be wrong, or just more domain-specific, bu my experience is people don’t complain that the video is 15-30 minutes long, is that it’s a video (and that long) when the information could have been more succintly and practically displayed in a text tutorial or a blog format. Basically “this could have been an e-mail”.
Not to mention that way people avoid having to go to YT which is yet another cesspit community-wise.
You are right that people have shorter attention spans ofc, but then again when it comes to tackling it it’s largely an issue of medium: in the world of coding you can convey easily copyable or testable instructions in text format maybe with attachments, that can be verified in up to 60 seconds… or you could post a 30 minutes long video plus ads. Why would anyone expect the Fediverse, with the kind of people who are naturally attracted to it, to prefer the latter, no idea.
Mods should be joining in on the celebration instead, in particular unpaid / community ones like Reddi’s.