1. If ww2 emptied the treasury then that's all the more reason to stay back in India, isn't it ? That's why they had come to India in first place.
2. If what you are saying is correct, then why didn't the British leave other commonwealth countries ? A whole lot is there which got their independence in the 60s and some in the 70s.
Bahamas, Bahrain, Ghana, Nigeria, South Africa, Sudan, UAE, Yemen, Kenya (they used ground attack fighters against rebels in Kenya) etc. etc.. a lot many more are there..
3. Who do you think was creating the civil disobedience ?
Hint :
Civil disobedience
Salt March
Quit India