I saw this effort to put Christmas back in the economic spotlight. I wish them the best. Meanwhile, if you see me around, “Happy Advent” or better, “Blessed Advent” is fine until sundown on Christmas Eve. “Happy holidays” is also okay. After that, Merry Christmas is great all the way through to January 10th this year.
Honestly, I never saw the problem with “Happy Holidays” as an alternative. Given the Orthodox devotion to Epiphany/Theophany as the apex of the Nativity cycle, I think we can easily suggest there are multiple Christian holidays the first two weeks of winter.