The wearing of them isn't, though. People were not hauling around their 70s hi-fi systems on roller carts to listen to music in their large headphones.
The original Walkman came with headphones [1], but they were light and fluffy. For a long time after, the trend was toward lighter, smaller. People wearing large headphones out and about are definitely a later wave.
If you’re old enough (and of the right subculture), you may have been hauling your 70s hi-fi system around, but not on roller-carts: https://en.wikipedia.org/wiki/Boombox#/media/File%3AChicago_... (also stops any complaints about these being too large :-) )
I was just about to write the same thing. Big headphones were of course the way most headphones were made initially. And it didn't matter until Sony released the Walkman allowing to have good audio in a mobile environment. For years though, they tried to make the headphones smaller, though being far away from todays in-ear phones.
I really think it was Beats what made people wear large headphones in the public.
The original Walkman came with headphones [1], but they were light and fluffy. For a long time after, the trend was toward lighter, smaller. People wearing large headphones out and about are definitely a later wave.
[1] https://www.theverge.com/2014/7/1/5861062/sony-walkman-at-35