They lost 74% of our treaty territory
A lot of them did return to their families, however the role of women in the factory was actually cemented in American and other cultures upon the war ending, so many women continued to work and even started careers. Cue second wave feminism.
Here are some reasons take your pick. Good luck! :)
Japan had modernized weapons
Corruption of the Chinese government-officials embezzled military funds.
Chinese army and navy had little preparation for the war
Japan had better war tactics and strategies
Chinese just finished the War of Opium and were weak
The majority of China’s massive population was not educated
