Because it's just another day, contemporary society rejects the notion of religion as a general so it has no meaning. People just expect so much of Christmas out of experience. In reality, Christmas is not "losing its charm", but as a person you are changing;growing up. I think part of the human experience in growing up is a trend from material possessions(As a kid) to realizing what's important in life - family ect.
If you think about it, it makes perfect sense. It's nothing to do with Christmas being "Over commercialized".