A lot of long videos have very little informational content but they become long because their creator rambles, repeats himself, tells shitty repetitive jokes and wastes time with sarcasm and then clarifying those sarcastic remarks because otherwise some people won't get it, etc.
Drachinifel is a prime example of this. The channel "WWII US Bombers" is an example of the opposite, somebody creating information dense short videos because he has laser tight focus and no time for joking around. (Examples chosen for the conceptual proximity of their content, historic military ships and historic military aircraft.)
I guess I've just been mostly lucky to avoid those videos. And to be fair, most of the longer videos I watch aren't "purpose made" for Youtube - they're recordings of lectures, conference presentations, etc., where the length of the video just happens to be a factor of the length of the original session.
Drachinifel is a prime example of this. The channel "WWII US Bombers" is an example of the opposite, somebody creating information dense short videos because he has laser tight focus and no time for joking around. (Examples chosen for the conceptual proximity of their content, historic military ships and historic military aircraft.)