1. Different economy model - Old economy just rely on resources, like agriculture, fishing, hunting, forestry. Each industry needed mimimal input,and its output was easy to distribute around. Modern economy rely on energy, capital, technolgy, so on while output needs international markets. Government plays an critcal role in morden economy to supply input and sell output.

2. Different environment - Old China had little interaction with international world. The current environment is very dangerous for China.

3. Free Market effect - profit driven investors and business pour their money and effort in place with high return/yield, ignore thore field that is critical for public quality of life. Government intervence in the ignored but important field is very important.