I agree with this point.

Maybe all education will get more and more similar to e.g. learning an instrument.

You can get everything from YouTube videos, sure. But a good teacher will help with things like knowing how to get a good repertoire for your skill set, what bad habits not to develop that will cripple your ability to learn more complex pieces over time, etc.

I think expertise in hard subjects will only become more and more valuable (as always), and thus harder and harder (and more expensive) to achieve.