Of course the great population growth of Chongqing and the rest of Sichuan was not due to just the import of beautiful women. If you understand the history of the WWII in China, you would learn that the Japanese controlled a good chunk of China, including all the coastal regions, most of the important financial, political, commercial, cultural, and industrial centers, ie Canton, Shanghai, Peking, Nanjing, Hangzhou, Suzhou, etc.
Chongqing and the rest of Sichuan province was chosen because it is a mountainous yet fertile region that was easier to defend than all those relatively flat coastal regions. Back then the Three Gorges were really narrow and treacherous to boats going upriver. Hence Sichuan became a safety zone for Free China.
Upon knowing Sichuan is still part of Free China, many refugees (rich and poor) fled to and settled there. While the poor could only take the clothes on their backs, the rich and government also uprooted and relocated much of the heavy and light industry factories, military industrial complex, cultural artifacts, school faculties, financial systems, and their respective trained and educated workers and staff and supporting infrastructure to Chongqing and the rest of Sichuan.
I heard many stories of many coastal cities' refugees who were residing in Sichuan during this time. Even a relative went to university in Chengdu that was created by the academic faculty who were relocated from Peking U and Tsinghua U.
So in the end Sichuan benefited alot from the war, it became a bastion of beautiful women, it inherited a very large and extensive heavy and light industrial complex and infrastructure, it inherited a large military industrial complex, it became more cultural and educated like as can be seen in Chengdu, and it got a big population boost.
Then you ask why has Sichuan been lagging the coastal regions recently in wealth? Well that is because the coastal regions have benefited from ideal geography, ie having seaports and being close to HK, Taiwan, S. Korea, and Japan where many of the foreign investors are from. But because of its inherent advantages as listed above, Chongqing and rest of Sichuan is fast catching up which will eventually lead to more and more of our famed Sichuan girls staying home to entertain their own local tycoons.