Joseph Bottum has a piece in the most recent issue of First Things on the disappearance of Advent. Here is how it begins (you need a subscription to read the rest of it):

"Christmas has devoured Advent, gobbled it up with the turkey giblets and the goblets of seasonal ale.

"Every secularized holiday tends to lose the context it had in the liturgical year. Across the nation, even in many churches, Easter has hopped across Lent, Halloween has frightened away All Saints, and New Years has drunk up Epiphany. Still, the disappearance of Advent seems especially disturbingfor its injured even the secular Christmas season: opening a hole, from Thanksgiving on, that can be filled only with fiercer, madder, and wilder attempts to anticipate Christmas."

When I was growing up, we didnt trim the Christmas tree until Christmas Eve, and that held in my siblings families until fairly recently. I wont talk about the advertising on TV and in stores, which this year began early in November, nor about the incessant playing of Christmas music, except to note that I know of at least one pastor who was berated by a parishioner because during what used to be celebrated as Advent, no Christmas carols were being sung at Mass!  A few years ago I heard a news-anchor refer to the Twelve Days of Christmas as the last shopping days before Christmas!