• looming demographic problem of ageing population
• drastic PRC gender imbalance, too many males and less females due to cultural preference to continue family surname.
• too few youngsters to support many old folks
• not enough workers for PRC industries in future
• not enough recruits for their military
Now PRC is not as poor as in the 1960's. Some can afford to have more than 1 child.
Singapore changed course from its stop at 2 policy earlier. But we are very much smaller country and easier to make quick changes in policy. Big behemoth like PRC, harder to stop momentum and change direction.