FWIW, I ran across this article that is pertinent to the "Western" vs "Japanese" bonsai arguments. It is well worth the read. Fascinating stuff, such as Japanese bonsai doesn't use the nation's time-honored "iemoto" systems of setting standards and practices for formal arts handed down via generations, such as in Noh, Kabuki and music. It uses the "modern social phenomenon of the exhibition, imported from the West in the Meiji era" to transmit accepted forms and practices and judge skills...
https://www.japanpolicyforum.jp/archives/culture/pt20100928160529.html
Another interesting passage--
"In bonsai circles in modern Japan, the most important criterion is assessing the value of a bonsai is its ownership history–ideally consisting of several generations of socially and historically important figures, particularly if they happen to have been influential in political or economic circles. By taking temporary custody of the tree and looking after it on a daily basis, the individual cultivator or nursery is able to bask in the reflected glory of the tree’s superior pedigree. In an extreme case, even a tree of no particular merit might be praised as a masterpiece if it comes from a sufficiently impressive lineage. This is reminiscent of the way that tea utensils are evaluated by connoisseurs of the tea ceremony."
And this:
"There are certain nationalistic bonsai aficionados who take this as reason to assert loudly that “bonsai was invented in Japan and can only be found here,” or to posit China’s
penjing, Korea’s bunjae, or even Vietnam’s
hòn non bộ as “enemies” somehow of the Japanese tradition. These people also treat the art of bonsai growers in Europe, North America, Australia, South America, Southeast Asia, and Africa as “offshoots” of the original traditions of China’s
penjing and Japan’s bonsai. These statements are as foolish as they are wrong, though. Today every region of the world is seeing the rise of unique forms of bonsai that match the cultural spheres and traditions in which they are developing. We should all accept this rich diversity and view it as a cause for celebration."