Culture is the sum of beliefs and behaviors of a society, therefore the socio-economic status of a society is a part of its culture.
I don't think you can say that. The very definition of "culture" means people within it can be identified with a single set of standards and rules, no matter of rich or poor. "Culture" should not be influenced by financial status.
As you said, culture is a sum of beliefs and behaviors of all people within a society. Especially when talking about a huge country like China, where many people believe in so many different things, the sum (or should I say "average") of all these beliefs cancels out almost any distinguishable differences. In the end, you get a society that practically only represents only thing: human nature. What you see is essentially a snapshot of what any human would do and could do certain situation. That of course covers a wide range of potential options that any human might choose.
The US in the 1920's certainly does not have the same culture as the US of 2016, just as China in 2016 does not have the same culture as China in 1970.
That's exactly what I have been talking about. Human behavior evolves and changes all the time, thus cannot be used to define "culture".
The problem with comparing China with a USA of an earlier time, and trying to extrapolate from that, is we would have to assume that the two societies would evolve in a similiar fashion. However, while there are indeed some similiarities, there are also plenty of differences.
Actually, we don't have to assume anything. Since the hypothesis is human of any nationality would behave in a similar fashion under the same social/economic situation. As long as you can show current China and the US in the 1900's are in similar situation, that should satisfy the premise. How each nation evolve has nothing to do with it. One is steady state, while the other is kinetics. Two completely different concepts.
To return to my original thesis, the legal framework of the PRC are based on the Republican values first expounded by Sun Yat-sen, and is most certainly based on Western philosophy. However, the mentality of the Chinese people are based upon a vastly different philosophy. Much like Communism, the Chinese pay lip service to these laws, but largely continues to follow traditional Chinese beliefs in their daily lives.
Again, you over-emphasize the minute differences and try to single out certain aspect of a highly complex society to explain certain phenomenon. This is very dangerous because you ignore other aspects of the society, which surely also contribute to the phenomenon. this is what happens when you subjectively examine a problem.
Additionally, what is the difference between Chinese traditional philosophy vs. Western philosophy? Deep down, they are very similar. Don't let names, such as Confucius and Aristotle, confuse you. If you look carefully, Western beliefs and Chinese beliefs are very similar in nature. Even the much celebrated Chinese medicine is very similar to what the West practiced before modern science and medicine. Chinese medicine believes in 5 elements (metal, wood, water, fire and earth), whereas Western traditional medicine believed in 4 elements (water, air, fire and earth).
And this makes sense because West and East had never been as isolated as we tend to believe. A couple years ago, archeologists discovered a 5000-year old tomb in the middle of the Gobe desert, where an ethnically (genetically) Chinese woman was buried wearing typical Germanic style clothing, Indian-style head wear and along with various Chinese and middle-eastern style artifacts (all of them consistent with the period, of course). The style of the tomb was purely Chinese. Apparently, our ancestors had been communicating extensively across the Eurasian continent. There have been tons of evidence consistent with this view. And the communication has never stopped, causing the different societies to mesh and influence each other. Thus, in the end, what we get is a huge melting pot of everything, East and West. All the perceived differences have been intentionally singled out to emphasize certain perceived superiority of one society over the other.
In the end, we as a whole are all the same. Again, statistically speaking, any perceived difference will be drown out by the large population base. Individually, on the other hand, we can be vastly different. But that means nothing when we are plugged into the society.