Well, in this world, no conditions seem to be permanent. Before now, there were great empires and kingdoms but unfortunately, some of these great empires and kingdom's has falling give rise to the existing nations. Dollar has maintained a great regime for many years but may not last forever. However, I don't think that the Chinese yuan will ever overtake or replaced the US dollar no matter how their economy is booming. The US has advantage over China even on the world economy, and there is also a language and social economy powers beside been a great war powers by the US over China.
China will only try to be the biggest economy but won't get the desired supports from the G7 nations. A tree can not form a forest. This is my opinions.