I'm currently living in US so I have the first hand experience to answer your question.
1. Cultural Influences
Do you know that on average American spend ~$US 500 to $US 1000 each year on X'mas presents to spouse, relatives and friends? My colleagues on average give away 15-20 presents per yr with value $15-$30/present.
Also for Western wedding banquet, most guests present gifts to the host, again not cash. Any idiot couples would love to receive cash , but it is the tradition here to present gifts, not cash.
2. Difference in living environment
a: Big House: Most Americans are living in houses about 2000 - 3000 ft^2 + garage + yard. That makes a huge difference in consumption behavior. Simply saying, if you are living in a big house, you don't want to leave it empty and therefore you buy more furnitures, decorations, pictures to hang on the walls, etc.
b: Cars: Average American household has 2 cars. That means you spend money on cars, insurance, gasoline and maintenance.
3. Medical costs: If you don't have insurance, you can pay a lot more to receive medical care. Just normal clinic visit, for instance in case you have a flu, Hong Kong you pay ~$150-200 per visit, but in US, assuming no insurance, minimum clinic visit is about $US 80 and not including medications.
4. Propety price: In general housing is more affordable in US. "Affordable" is in a sense relative to your regular income. In that sense, you don't need to save a lot to buy a decent house or apartment.
5. Political stability/ Retirement benefits: I read Wall Street journal once saying that since US is politically more stable and retirement benefits are better , therefore there is no incentive for people to save more. I agree with that but it is a much smaller factor
In summary, I don't think it is whether you are Chinese or Americans, but the living enviroment in US encourages you to spend more. Trust me, most Chinese living in Americas spend more and save less, including myself.
美國的消費模式是享樂形式,如我無記錯美國是每星期出一次糧(這個如有錯誤請指正),佢會覺洗晒好快有糧出,所以可以先洗未來錢,中國人由細己知積穀防飢的道理,所以愛儲蓄
參考: me