It is part of our job to lecture, but that's not our only job as an instructor, and I wouldn't even say it's the most important one. Our job is to assemble a coherent course -- typically involving lectures, homeworks, exams, etc. where everything is tied together, and where I try to chart a coherent path through the material, so that the students have learned a subject by the end.
Once I was teaching vector calculus, a subject which 3b1b covers, and I showed a couple short clips in class. I also shared additional links with my students and encouraged them to watch. As instructor I try to make good use of any and all helpful resources which are available, and 3b1b is certainly one of them!
> This video is not an outlier.
I would argue: this video is an outlier in that it's "best of the best". I've seen other videos. While they're usually "good", they're also usually very dry.
So good videos aren't a new thing. But I think there's MUCH more decent and excellent content coming out these days.
Also there's the part where they can't assume their target audience is a bunch of students who have to learn a subject so they really do try to make it as layman as possible.
I wish there was a big list that had links to the best lectures and the accompanying book for so many things.