Without the solid foundation laid in nearly 30 years prior to 1978, China might not have the opportunity of attaining an miraculous achievement in her economy within the next 40 years.  What the solid foundation was?  It was because of her heavy industry and military deterrence acquired in her own right under the worldwide blockade.  (Though, she did receive some assitance from former Soviet Union during 50s.) 

The deterrence power that China displayed in Korean War and Vietnam War made US must seek the policy aimed at bringing about rapprochement with her.  After she had safeguarded her national security, China then released all her social power which had been long "suppressed" so as to reinforce heavy and military industries.  All Chinese people, especially those in rural areas, then sufferred with pittance to support the national goal.  After 1978, they were emancipated; with outburst energies, now they made China the biggest manufacturer and largest clientele of the world. 

Some people may say during the four decades corruption, widening gap of the rich and the poor, and lagging behind in some cutting edge of technologies due to lacking of long-tern strategy have emerged.  I agree.  Yet I still have full confidence in China that she will have her own ways to grapple with these problems.