Looking back at my teen years, the things that made me still into Christmas were:
1, list + surprises. There needs to be something unexpected. I get that teenagers know what they want, but if it is exactly on the list, you can't expect them to be that excited on Christmas, it is more the excitement of an Amazon delivery.. something they ordered and are now waiting for. Personally I would get them what they want, but add something else, maybe in a fun/unusual way, so that they have a bit of surprise/mystery.
2, Getting them involved in doing things. They can cope with responsibility now. Let them plan and cook one of the meals, or plan one trip out, or plan a movie night (pick movie, buy snacks, get things ready etc.) or a game night etc. Give them something to do, and some investment in the festival, because they made it happen.
3, Tailor activities to what they like. When I was kid, Christmas celebrations were santa clause and magic.. as a teenager though, for my family it was more of a party.. we could invite friends, had other cousins, more games, party games, drinking (for the adults) music, dancing, kareoke, late night board game sessions etc. Stuff that teenagers like. I think one of the problems that parents have with the "magic" being lost, is that they try and hold on to the child period too long, and then wonder why their teenagers don't love Christmas any more.
The magic isn't in santa or presents though, its in family and time together, and that has to be tailored to the age of those involved.
Now that I have my own young children, our family has flipped back to Child-like magical christmas, and its lovely... but when he is older, it will be back to parties and teenage christmas again, and the cycle will repeat.