Boy, am I with you on that. I have a collection of Christmas music that rivals many people's everyday music collections, and very, very little of it is from the 20th C., and what I do have is mostly derivative of earlier times anyway.
Randfan mentioned getting rid of nativity scenes. I haven't even gone that far; I've got a couple small ones that I still use. To me they're just mythological dioramas that I view as being no different than my display of stuffed figures of Yukon Cornelius, the Abominable Snowman, Rudolph, Sam, and the Misfit Toys.