Brooks Jensen on the LensWork podcast argues that the most important part of photography can't be taught. You can flood Youtube and blogs with information about tools and technique, but when you try to learn about what comes next, there's a natural dead end:
“It is so easy for beginning photographers to get swept up in that initial learning curve and to think that is the great challenge in photography - mastering tools and techniques. My contention is that mastering tools and techniques is the preliminary step. It’s like graduating high school. You haven’t really done anything yet. All you’ve done is prepared to do something...OK, you have technical mastery. What are you going to say?”
Some photographers give up at this point and some become artists.
I'm not sure I agree that none of it can be taught, though. I think artistic expression can be taught, but by example, not through a lesson plan.
I'd also prefer not to learn artistic expression from a photographer. Art includes a universe of practices outside your own. Why limit yourself?