Here is a bit sad story of P. purpuratum in Hong Kong. Hopefully, the situation is better at the vicinity of Hong Kong (Hainan, VietNam etc). It seems to do well under cultivation and it is a common species. It grows well for me and flowers every year, but it doesn't seem to clump for me. I got mine from Carter & Holmes about 4 years ago.
Well, I'm guessing that people in different country may have different priorities (sadly), even though it is under CITES App. 1 (same category as Giant Panda).