As one who lived both in and outside US, I would say it is materialism.
I see American individuals working long hours in corporate careers, trying hard for their corporations to increase their profit margins.
American culture preaches hard work is sacred. Keeping busy is good.
They do this even if some else, like corporations benefit more than them. They don't have enough sleep and don't spend enough time with their family or spend time on spiritual and social needs. Americans spend less time on vacation then others.
It seem the American Christmases appear to be very materialistic.
Contrast these with other cultures. Others spend more time with spiritual and social activities including family. Hard work is applicable only if there are needs or if it beneficial to them They have less stress and have better sleep habits and also have healthier diets. Consequently they have less problems with obesity.
Some of these cultures intentionally restricts themselves from being more wealthy or materialistic. Christmas has more emphasis in spiritual areas such as the birth of Jesus and not much about gift-giving
I am not judging American or others. These are purely based on observations and there is no wrong or right situation. Every culture is free to make their choice.