To a great extent, mass-movement SBNR is what happens when spirituality encounters the idea of free society, and when spiritual events occur to people whose identity has been formed in a modern secular context. Thus, as the secular spreads, so does SBNR.
It was the secular and free-market milieu opened up by the Chinese Communist Party which allowed the qigong movement to happen.
In Japan, SBNR is usually quite strongly separated from the religious. In America though, the large religious population implies more common ground. Interestingly the UK is mostly far closer to the Japanese situation.
Seeing that, I understand some of the conversations I’ve had with my American pals, who don’t perceive as strong a line between spiritual and religious. This is just one example of the currently increasing divergence between Europe and the US.
SBNR may thus be more European than American, especially since the US Enlightenment was not anti-religious in the same way as the French. But probably not much more. (Glenn was totally SBNR and they don’t come much more American either.)