A long post
The historical record looks a little different from the folk model.
There is nothing extant from the period of Zhan Sanfeng that even alludes to him being involved in any martial practices. He wrote about alchemy not boxing.
Three hundred years later Chen Wanting appears to have developed a syncretic martial system based on the thought and method of Qi Jiguang, and perhaps the writing of Chang Naijiao. It may be that Chen Wanting was poised to rise in the Confucian bureaucracy when the Ming dynasty fell and the Qing dynasty arose. As the Qing were a non-Chinese military society the possibilties for military advancement for a Han were severely curtailed. This may be why Chen Wanting stayed home and developed his martial arts.
The historicity of Jiang Fa is not well established. He appears in no official records of the period, though there is a portrait of Chen Wanting that shows a bearded figure standing behind him. The Chens identify this as Jiang Fa, which would make him a disciple not a teacher (the teacher does not stand behind a seated student in classic portraiture).
Zhan Sanfeng and Jiang Fa mythology aside, I think I know what you are getting at bamboo_leaf. The real problem is that transmission has not followed a communist ideal were all Chens got to share equally in the Taiji pie. Its a feature of peasant societies that the world seems finite and so the world’s resources seem finite. This means that if your neighbour is getting ahead they are getting a bigger share than your family. Its ok for them to survive, but if they expand it will ultimately be at your expence. This has been a subtle feature of Chinese society from the most ancient times.
Because the boxing skills were a means to local power in the Chen village there was a quiet competition for the best skills even between the various families of the same clan. It appears from the historical record that the best skills remained in the direct line from Chen Wanting through Chen Changxing through Chen fake. Yes there were many skilled boxers in the village (it is not certain but the northern advance of the Taiping rebellion may have been stopped at the Chen village), but each kept a little bit secret from the others.
When we come to the 20th century we are in a period of terrible decline. China was ripped apart by colonial powers with no long term interest in the infrastructure of China (a feature of the unequal treaty system). It appears that the overall level of boxing in the Chen village had declined due to poverty, social dislocation, lack of central authority, and widespread opium addiction brought on by despair. When Chen Fake went to Beijing he took with him the highest level of knowledge still remaining in the village. After his departure, and until Chen Zhaokui’s return in the 1960’s, there were no practitioners of the first rank left in the village.
In Beijing, Chen Fake taught openly, but not completely. He taught a “public” form, based on the form of his grandfather Chen Changxing, but not as detailed in terms of precise silk-reeling jings. This sharing of more private knowledge may have been because he needed to compete for position with other high level Taijiquan practitoners in Beijing at that time. This form became the basis for the Chen of Feng Zhiqiang and Hong Junsheng. More detailed than what was still happening in the village (they continued to do an even simpler version of the form), but still not the “lineage” form.
Chen Zhaokui returned to the village and began to teach the public form, this became called by the villagers the Xinjia, or new frame, because it seemed as if this must have been created by Chen Fake once he got to Beijing (Chen Zhaokui said it was his father’s form). Hence they call the village form the Laojia, or old frame.
Chen Zhaokui had four disciples that he taught the lineage form to: Ling Jiang, Cheng Jinzhai, Ma Hong, and Wu Xianbou.
So what we have is an old style generated in the 17th century, cross-fertilized in the village until the breakdown of the old Imperial system, yet having at its core the skills of the main decendants. Better than most of their contemporaries, not by genetics, rather because they were receiving better more-detailed training. The lineage core leaves the village with Chen Fake, who was acknowledged as being peerless the Beijing Taijiquan community, and he never returns. When his son comes back he is teaching more of the old core material, which comes to be called the new stuff.
The real dilemma for Chen practitioners is that the best of the style left the village a couple of generations ago, so is it “the source” for the best Chen style?
As for “… yet their TC more closely follows the Yang style…” I actually don’t understand what you are saying. It seems to me the other way around.
“The heart of the study of boxing is to have natural instinct resemble the dragon” Wang Xiangzai