Thinking a bit more about the seasonal business cycle and Christmas as a macroeconomic phenomenon, I think it's important to understand that the spirit of Christmas is about more than presents. And, no, I don't mean spiritual values.
I'm sitting right now in a neighborhood coffee shop. The two baristas are wearing Santa hats. Two wreaths are hanging in the windows. Poinsettias are on the tables. There's some tinsel, a couple of tiny Christmas trees, a few Christmas ball ornaments, and a special "holiday blend" of coffee beans is for sale. My wife's parents and her brother flew to D.C. from San Antonio a couple of days ago to pay us a visit, and my dad and stepmom are coming down on a train later today and will stay in a hotel tonight. Kate and I are going to be hosting our family and also some friends for a dinner that will feature a larger and more lavish meal than we would normally cook, and we had to rent a table and some chairs to accommodate everyone.
And you see this kind of pattern playing out all across the city. People aren't just buying gifts for one another, they're engaging in semi-frivolous decorating and entertainment activities along with a lot of extra travel.
Clearly some of this Christmas-related economic activity is just pushing consumption around. From the airlines' viewpoint it'd be better if family visits were spread evenly across the entire year. But most of the rest of this stuff doesn't have that quality. It's not as if America's buildings are inadequately lighted during non-Christmas seasons and if we didn't make all these Christmas lights, we'd just consume more regular lights instead. Or take Christmas music. A lot of people seem to enjoy hearing their demographic's artists doing new performances of old Christmas songs. I'm partial to A Very She & Him Christmas myself. The fact that there's demand for this particular form of "new artists sing old songs" creates a lot of value that would otherwise dissipate in a popular music industry that in other circumstances is very novelty-oriented.
Obviously the presents are in a sense at the center of this. Children are very enthusiastic about presents, so people grow up with lots of positive associations around Christmas and a strong desire to engage in seasonally appropriate activities. But the actual pull on the economy is much bigger than the gifts.