I love YouTube but my problem with the content of YouTube is that almost all videos are introducing you to everything every time.
For example, there's this science video about this interesting property of fire right? They start with what's fire, when it was invented, what led to be studied this way and then they deliver the money shot. It is O.K. to be introduced to a topic once but it is brain wrecking to be 101ed every time. They are doing it to increase the watch time and the ad revenue and its horrible.
Forcing the videos to be short makes them deliver the gist quickly, TikTok videos that are trying to the introduction 101 thing are just as horrible, when a video is over 1min I'm very skeptical and feel the urge to move on.
Of course in-depth videos need to be long but those are not that many actually. From the pop-sci genre Veritasuim does it well but that kind of production takes long time and they publish videos every now and then. With the race to pump videos as quickly as possible, the short format is the better since you can get the content quickly and if you want to know more about it you can actually read about it. Which is how you actually learn anything BTW.