I'm pretty sure there would still be some type of Winter Celebration. This is because across the world and throughout people groups of all languages there are celebrations of the seasons. I'm not sure why people would want to celebrate less sunshine, shorter days and frigid temperatures but they do. Perhaps they are celebrating change.
It is for that reason alone that we must continue to celebrate CHRISTMAS! The only way mankind could ever achieve lasting change is because of the incarnation. God became a man so that men could become the children of God. Our understanding and receiving the gift of God which is through faith in Christ alone and by grace alone is the way we truly connect with Christmas. I hope that this year you will celebrate more than ever before because you realize that JESUS is the REASON for the SEASON.