There's not just Vietnam, there's quite a few other countries that offer better manufacturing options. Burma, Bangladesh, Cambodia... Actually Cambodia poses a problems for Chinese companies that have moved there...

https://www.washingtonpost.com/world/chinese-companies-face-culture-shock-in-countries-that-arent-like-china/2015/08/14/a048eb64-3bbd-11e5-88d3-e62130acc975_story.html

The main issue is the inefficiency in Chinese manufacturing was previously forgiven because costs were so low. Now, inefficiencies have been revealed and that's going to mean that if these companies are to survive, there's going to have to be a lot of cost trimming taking place at various companies.

For sure China is far from doomed; but over the next few years, it's going to have to start getting its act together. Even the Chinese manufacturing companies are leaving China!

At least they're moving in the right direction, in the tech industry. Being more innovative, getting new products to market very quickly...