So you don’t think that automating production and freeing people to do what they enjoy while improving their standard of living is a worthy goal? Yes, we are moving in the right direction, but there’s still an astonishing amount of manual labor in terrible conditions happening in poor countries to produce cheap stuff. For things that are automated elsewhere, but it would cost more than the cheap labor there. As I said, it’s sad.

And yet we’re still far from succeeding. It’s sad.

Approximately. It differs a lot and the upper limit goes down with age. It also depends on loudness. I could hear up to around 16 kHz in my early twenties. I doubt many adults would hear 20 kHz, unless it was very, very loud.