Why emerging economies are growing faster?

Very fundamental question. Why emerging economies are growing so fast. What is driving their growth? Is it just the fact that there is room to grow and they have cost advantage over developed world? Or there are some other reasons. What are these reasons?

I feel that other than those two obvious reasons, there are other key factors. Every emerging country has found some niche. Far east countries have manufacturing as their key base for growth. India has services like IT and call center. These things are effecting their growth coupled with their explosive population growth which MNCs from developed world are trying to tap into.. is leading additional flow of new investment. Also, all of these countries understand that there is no gain without pain. Somber example, china has kept strong control on costs by artificially keeping cost of manufacturing goods low most likely by keeping currency under control. What ever condition of infrastructure in India may be for common or poorer segment, India is continues to provide decent infrastructure to IT companies. Also, in India there is immense local consumption and imports are still expensive. Brazil.. I guess found niche in alternate fuels and tourism.. which continues to make it grow at faster rate. However, there is big risk in these economies, mostly political.. Corruption is still high and rampant but as long as it doesn't come into growth it is fine. 


Once these economies get into growth cycle and achieve decent infrastructure and local consumption, it becomes vicious circle and then leads to hyper investment from financial community which leads to these exponential growth numbers. Once they reach to certain level of basic infrastructural support, these economies could be decoupled further with developed world and can sustain more or less on their own.

What I heard on economist today is very true.... That these emerging economies will continue to do well as long as developed world is limping around. If developed world gets into recession, this vicious circle of growth breaks and leads to slower growth in these emerging economies as well. However, as long as developed world keeps limping, emerging economies will continue to grow at much faster rate. 

Any other thoughts??