Here is a list of certain issues, events, etc, that were once heavily the subject of day-to-day conversations and featured extensively in the news, but are seemingly mentioned much less now than before (in no particular rank order) or at least kept lower-key, despite almost all of them still existing in some form or another.

Covid (most recent).
AIDS/HIV.
Binge drinking/late-night aggro in town centres, etc.
Teenage pregnancies.
Feral youngsters.
'Ch@v' culture.
Happy slapping.
Joyriding.
Conflicts in Syria and Iraq.
ISIS and Al-Queda.
The EDL, Britain First, etc.
Violent films and 'video nasties' in general.
'Explicit' content in popular music (not just profanity).
Muggings.
Armed robberies of shops, banks, etc.

To name but a few.