The main reason those companies shut down, or are in the red, is because of poor management and bad planning.
You can always say that. Well-managed company can even survive world-wide economic depression, for sure. Still, the exodus of such company relfects worsening business condition in China.
I heard that Samsung's new plant in Viet Nam will service Europe and other areas. It may service S.E. Asia, but it is only a part of it.
There could be more opportunities deep inside China. However, as export hub, they may not meet the requirement of many foreign companies.
From what I see, there are no indications of an exodus, however one company's decision to relocate. The reasons for this move can be numerous, but in my experience, the larger companies will retain a portion of their production in different areas.
Therefore, the final product being shipped to Europe will have one component made in the Phillipines, one made in Malaysia, one made in Singapore, one made in China, one made in Japan, and finally assembled in Vietnam and put on a container for Germany.
This is how costs are kept down and all their eggs aren't kept in one basket...