EnviroKid's birthday is on Christmas Eve. On that day, we have a special family outing, dinner menu of his choice, and cake. Then we go to late-night church and the focus shifts to Jesus and then to family gift-exchanging and celebration the next morning.
In late June, he has a half-birthday party with gifts and cake. On the party invitations, under "half-birthday" we write in small letters, "His birthday is on Christmas Eve!" Nobody ever has reacted badly to the idea.
Yes, there are some people who can't come due to summer vacation plans, but not nearly as many as wouldn't come to a party on a major holiday.
My uncle in Hawaii has an early-December birthday and likes to make sure that EnviroKid feels acknowledged on his actual birthday, so he always includes a gift in birthday paper in the box of Christmas gifts. He does NOT send a half-birthday gift. We let EnviroKid open this, and any other gifts people have designated for his birthday, on Christmas Eve morning.
Other than that, HE DOES NOT GET BIRTHDAY PRESENTS ON HIS BIRTHDAY but on his half-birthday, so I don't see what's "materialistic" about it.