A thousand years means little.
Keep in mind that Galen was the primary source of medical theory in the West for over 1000 years as well. That just means any errors were retained for generations. For 1400 years, people believed his false understanding of the circulatory system, until someone figured out that the blood circulates through the body with the heart as a pump. For 1400 years, since a smart man dissected animals and developed medical theories, people did not know that simple fact of physiology. For 1400 years, people were doing it wrong. And that was based on dissection.
TCM is not based on dissection, but philosophy, an understanding of harmony within the body and Qi and meridians.
It has less credibility as Humorism, which was the foundation of much of medicine until the 1800s in the West! That was around longer than acupuncture probably. At least that is based on observable bodily fluids.
And of course, the Chinese believed that China was the centre of the world, and that the world was flat until European missionaries (Jesuits scientists were respected by the Chinese as good astronomers actually) informed that them the world was a sphere in the 17th century. The West knew this since the ancient Greeks (the main issue in the West is whether the antipodes were inhabited or not).
Also, Chinese people were crippling girls for life for the sake of beauty. And they were unable to deal with the infections which often arose from foot binding which killed many.
So, when it comes to medical knowledge, ancient knowledge is not a bonus.
And even for modern advances, it often refines and discards previous understandings and knowledge when it has been found to be lacking.
Many tribal people all over the world are using natural recipes and they are working very well, but nothing written on ” scientifics ” books.
To disregard scientific advances and knowledge for folk medicine is quite an interesting thing these days. Yes, tribal people have many interesting theories and remedies and treatments. Some of them work. However, NONE of them are replacing bodily organs, eradicating diseases, or reattaching limbs. They cannot deal with mental disorders either.
If most ancient aspects of China have been discarded for new things, there is little to think that medical science is one thing which should be retained.