Earlier quoted context omitted.
It needs critical mass, but then it cascades. If you read through the description, what they talk about is that the culture is built around the idea of the individual being part of something bigger, and that consideration and respect for that something bigger (other people), is core to your own identity. That's not hard for a lot of cultures, but it's almost impossible for most cultures in the Western hemisphere, and…
The cracks are already there though in Japan where this is starting to fall apart and has fueled a substantial rise in anti-immigration sentiment there. Particularly at specific groups that are not assimilating (but affecting basically every immigrant). I feel like half your post is dancing around not saying this.
I'm saying that culture spreads through fear of being ostracized and the cost of not conforming to that culture. This is true in any country. It seems Japan has a "broader" and "firmer" culture that is rooted in respect to others, but it would take some serious effort for a similar culture to take hold in Europe or the US, I think.
A sense of "non conformity" leading to issues is not unique to Japan though, in Europe it is described as a problem with "multiculturalism".
The British (of which I am one), have spent thousands of years stealing the best bits of immigrant culture but seem to have forgotten that (or have been unable to absorb, for whatever reason), for the last ~60 years. That's leading to a rise in far-right sentiment and a growing desire for mono-culturalism. I can see evidence of that in Germany, France and other European nations. I could easily imagine it appearing more in Japan.