I think live performance music is still one of the few things in this hyper capitalist world directed by the performers. I base this absolutely no information expect the interviews I've seen, but it's my impression that performers are heavily involved with everything in a live performance, including the price setting.

That is to say. I think the artist just like the idea of the tickets being affordable to allow their younger and less well off fans access.

I think any argument here has to acknowledge the artists rights in this. Charging more might alleviate the issue, but if private ownership of the performance is to have any meaning, it must include the right to set a price below the market rate. If the artist wants to be "economically inefficient" we as a society must protect that right.