> What is the relevant difference between axe-handles and music?

Music is more than a product -- live performance is a social experience, not just private consumption. People go to see bands live for many reasons other than the rendition of notes they could get from a recording: they flirt with other concert-goers, they experience mistakes and improvisations by the artists, and they drink and dance in public.

Similarly, good teaching is not a solitary or entirely reproducible event. The best teachers I've ever had were the ones who could get students talking to each other, generating and assessing ideas faster than any one pupil could alone. You can't get the same experience reading a textbook or watching time-delayed streaming video of a lecture. I'm not even entirely convinced that online interaction can pull it off, at least in areas like history and the arts, where subjective and emotional arguments are just as critical as hard logic.

> What is the relevant difference between axe-handles and music?

Interaction: calling back to the singer, requesting a song. Fidelity: being right there. Shared experience: being right there with a whole bunch of other excited people.

I've had tremendously emotional experiences listening to recorded music, but none so potent as hearing the same song live.

You might extend this to teaching: a recording of even the greatest lecturer can't answer your question.

Further to the discussion, though: mass production increased the base quality of tools like axes and knives, and improved efficiency. However, if you want something bespoke, mass production doesn't care. I like my semi- and full-custom knives: they were made for me, according to my specifications. Modern tooling can bridge the gap, too, yielding full-custom items of the same quality as mass-produced items.