I agree that the 12 days of Christmas starts on the 25th, so not really relevant to modern day life.
If you look up the Liturgical year, then your first Winter fast in preparation for Christmas Day should be on the 15th November. But the start of the countdown starts at the end of October. The Liturgical year swaps between the old and new calendar dates.
So from a religious aspect (depending on your religion of course) it's quite right to start in November. From a old style baking/food gathering perspective that started from Harvest Festival.
I've always shopped for my DD's, October born 1985 Birthday whilst Christmas stuff has been in the shops. The New Disney Film had already been advertised, or what old one was being released on Video and the merchandise was in the shops, in October.
We don't/I didn't do Adult presents, or stockings, but I always did Christmas Eve gift bags, presents don't always equal tat.
I theme rooms, but everything is put away. I had my loft boarded, wherever I lived, so I had storage. Or I donate it.
I do two Christmas markets and a Christmas day out each year, this year it's going to be a stately house, without buying anything except something really wanted for me. I couldn't do that if it didn't start until November.
Early start doesn't necessarily equal consumerism.