You have a deep understanding of modern Chinese history. Some people find it difficult to understand China's development only from the past 40 years of history.I agree with you. Most of the Paks here will blame it on last 40 years of corruption of the elected governments. The truth is while they have no helped but the countries problems are far bigger than Bhutto or Sharifs.
You see both countries might have been set up about the same time and China did look poorer. But it was all cosmetic. The Pakistan we had in 1940s, 50s or 1960s looked ahead of China. However that was not because of indigenous source. It was all British colonial legacy and American aid kept the country shining compared to China.
But a critical analysis will tell you China overtook Pakistan between 1950 and 1970. In this period China over hauled it's society at the root. It planted seeds of a new culture and society. So China may have looked poorer but in fact she was investing in her people for a better future. For instance by 1970 Chinese literacy was way beyond Pakistan. In short Chinese invested in their society and were ahead of Pakistan by 1970. This was laying the seeds of future success.
To put it in brutal terms Chinese ever since 1920's well before even CCP took over and birth of modern China had The New Culture Movement which was somply "copy the west".
In our part of the world it was other way round by saying "let's go to the past". The Chinese society inspired by the west to look forward. Our society repulsed by the west decided to look backwards. This is the reall povery that Pakistan suffers from.
The New Culture Movement (Xin wenhua yundong) was a movement in China in the 1910s and 1920s that criticized classical Chinese ideas and promoted a new Chinese culture based upon western ideals like democracy and science.
Chinese people generally do not compare the development history of China and Pakistan, because there are some views that will be regarded as criticism of Pakistan or the export of ideological and political systems.
Personally, the development history of Pakistan cannot be separated from the war after the founding of the country, the situation of the Muslim world and the Cold War.