My experience has been that everyone sang. We had a men's choir here for many years.
Many things contribute to people not singing: song leaders who are hard to follow, but mostly loud amplifiers that drown out everybody else.
Once here a couple of years ago a band from out of town sang at Mass here. I guess they sang, all I heard was the artificial drum beat from their huge speakers; BOOM -BOOM- BOOM, it sounded so good when it quit.
I think our whole society had become spectators rather than part of the group. Music has become loud guitars, etc without any good rhyme or rhythm to follow.