In order for China to drop down other nations have to get out, and until they find a cheaper and better place they are not going to get out.
Right now facebook and apple and some other big ones are switching their work force to India slowly, they are not doing it right away but they are doing it slowly, that means eventually one day there will not be any apple product from china and most of it will be from India with some of it from other smaller nations like Vietnam or whatever. That is why I think China is buying so many companies out and they are building so many of their own companies, because they know that building and manufacturing stuff for other companies will eventually end, so they need to have their own source of income in order to keep being a big power and they are doing that very well too.
This is a very bold move for Western companies to move their production in other countries, I have heard that Apple is on its last preparations to go to India for the production facility, this will be a big blow because Apple have a lot of factories in China which will surely affect labor force.
China will remain as the manufacturing powerhouse for the next few decades. They have the perfect combination of productive workers, low wages and lax regulations. There are countries such as India and Indonesia, where the wages are much lower. But they are plagued with issues such as red tape, bureaucracy and unproductive workforce.
The lax regulations in my opinion is the reason that they have a cheap labor, with workers not having a safety work environment and for this reason the costs are cut into just paying wage for the workers, they also abuse the fact that Chinese people are industrious and use it to get them work for longer hours. Regarding red tape, I do not have that much say but they have a very strict policy regarding corruption, this is the most admirable thing that I know of (I might be wrong in this).