Asia is huge, and there are more powerful countries in it than there are sociopaths in the American government (which is to say, a lot). China is already one of the main sources of cheap labour and represents much of the manufacturing done in our globalized economy. What isn't done in China goes on somewhere else in Asia. Japan is also pretty powerful, but it's not like island nations can become valid empires or anything (That means you, Britain!!)
It is important to remember that Asia is a continent made up of many diverse countries and peoples. There are many countries that could become global powers because they have inexpensive skilled and unskilled labor as well as abundant natural resources. These would be countries like China, Japan, and India. Other countries to not have those advantages.
Asia has something that the entire world desires, a cheap skilled labor force. Foreign companies are moving to Asia in order to utilize this cheap work force, which causes the economic growth of these countries. China has become one of the worlds strongest economies and is starting to take control around the world.
True, there are many increasingly powerful sovereign states in Asia, but not all of them are doing so well. Japan, for instance, once a relatively powerful economy, is having problems dealing with the effects of globalization. The country expects to see a population shrinkage in the years to come. Many of the countries throughout Asia have a very strong sense of "patriotism" to their specific culture and way of life, and I don't see that ever being any different.