I obviously didn’t make myself clear: you said the change was only significant “because they’d grown up with it.” That, to me “implied” that it was “a meaningless tradition that they missed for sentimental reasons.”
Perhaps I read more into your words than you intended: if so I apologise.
What I am saying is that the “Merry Christmas” greeting is both a blessing to the other person, and an opportunity to witness for Christ. That is why the imposition of “Happy Holidays” amounts to persecution of Christians.
I met retail people who said “Happy Holidays” to me, to which I always replied “Merry Christmas!” The reply was always a variation of “Good on you! I wish I was allowed to say that!”