I think there will be a return to shorter long-form content (~40 mins --> back to ~20 mins) .
There has been a trend in the last two years of content getting longer and longer, sometimes reaching even 1 hour+ duration. I myself am guilty of this, having made a 2-hour tutorial on Obsidian.
However, I think that this will no longer be the meta within 2026, as I think that the advantage that it once provided will begin to be lost.
The original thought was that by increasing AVD, you increase the algorithm's tendency to drive views towards your video. The amount of watch time is, of course, one important known factor in YouTube's algorithm.
But it was probably more likely the case, I think, that this was due to a supply-demand asymmetry rather than an algorithmic blip. In simple terms, there once was a gap where there weren't as many long videos being produced.
However, now that there's a lot of long videos being produced, the advantage will go back into people with more data points, i.e. more videos.
The other main advantage for shorter videos is that these videos are much quicker to produce in terms of time. This first-mover advantage will be significant for channels that take advantage of time-based supply-demand asymmetries (more simply known as "trendjacking").
Lastly: shorter videos can reduce the cost of risk of a video flopping for an individual creator. This is specifically for situations where making a 20-minute vs. 40-minute video has significant resource limitations (YouTuber, editors, etc.).
The 20-40 minute range still seems right for a world where TV viewership is a much bigger part of YouTube. There is also still a strong case for 10-15 minute videos.
In short: this is somewhat controversial, but I think very long videos will (and probably should) become shorter. With such a large increase in supply of super long videos, viewers just don't have the time to develop the habit of watching these videos in their day.
It's also probably more fun in many cases for both the creators and editors.
That said, this is all on a case-by-case basis of course.
