Do Phones Ring Anymore?

On the way to my office, I heard a phone vibrate and thought it was mine.  Wrong.  Turns out that most phone vibrations sound the same.  Ringtones are sometimes the same, but it's easier to have a unique ring than a unique vibe.  I think kids these days (and older people too) leave their phones on vibrate.  Sometimes I think they're on silent because I see people pick up their phone all of a sudden and answer it.  I definitely hear less ringing from phones than I used to.  I wonder what's caused that shift away from an audible (ok, I guess you can hear a vibration) notification.