I was born in 81. All the Christmas activities were school-based - carol service, nativity play, Christmas fair.
Other than those, we'd give cards to everyone in our class, help mum bake stuff, decorate the house - no earlier than about the 15th December. We'd go to a Christmas tree farm to pick out a tree, make paper chains (I still do) and most of the decorations were natural greenery that we went out to gather (when we were older kids we went out to do this on our own though, it wasn't a family thing). Mum also had us clean all the brasses, which we enjoyed, despite the Dickensian workhouse vibe.
None of these things were done with any fanfare, they weren't events, they were just part of the preparation for the event.
We didn't watch any Christmas films before Christmas Eve, and none of the specials were on TV before then either - now they seem to start at the beginning of December. Going out of your way to watch Christmas films wasn't really a thing then either - you just watched what was on the telly, and some of it was Christmas-themed, most of it wasn't.
Advent was a distinct time - the point was to wait - and you didn't start eating fancy stuff or chocolate etc. before Christmas Eve. The only exception would be a mince pie after the school carol service, at the PTA fundraiser.
I still do it this way, in fact my tree goes up even later these days, usually around the 20th. For us, Christmas is a time to feast and rest and enjoy old films while day drinking, but it doesn't start until the 24th. Two weeks of it is plenty, and I like the anticipation and preparation for it during Advent.