The 20th century did a number on music technology. Radio made music transmittable. Cars made music mobile. Speakers made music big, and silicon chips made music small. But headphones might represent the most important inflection point in music history.
That article doesn’t go into it, but I also think it’s interesting how the hardware we use for playing back music affects the way the music’s made. I remember reading an article about a reasonably big name producer (name escapes me now) saying he was going to mix tracks so they’d sound alright on Dre Beats headphones, since that’s what everyone’s using.