Of course, the system has to protect itself from those who might never relocate. In my case, i plan to reallocate. I cannot resign now because if i resign now and IRCC refuses the application, i will be in bad situation. But i can write in the letter that i will resign as soon as they approve my wife application. Hope this will work.
You can continue to send information as your application progresses. Saying you will resign provides no actual guarantee. Based on what we have seen people are asked to provide more information during the application process in situations like yours.