My first memory of the Sony Walkman is from 1981, when I saw a conductor I knew from Salzburg (how I wish I could remember his name, though I remember that he looked a lot like a young Peter Lorre) walking down the Kärntner Straße in Vienna listening to a recording of Lulu on one.
He took off his headphones and let me listen. It was astounding.
If I had a pair of headphones myself, I could have plugged them into his Walkman and listened with him. The Walkman was originally designed with two headphone jacks. Listening to recorded music was not generally considered a purely private activity in the early 1980s.
My early 1980s Walkman eventually stopped working, and when I looked for a new one, I found that the company no longer made Walkmen with two headphone jacks, and none of the competitors did either. If I wanted to share my high-quality outdoor mobile listening experience, I had to buy a splitter.
This is not as much of a statement about technology as it is about the change in the way we listen to recorded music.