You must also consider that the sweat from your foot is largely in a vapourous state. When water is a vapour it will pass through the pores of the leather much more easily. So the submerging a cork innersole comparison is not very relevant. Just think of gore-tex, it is tested by submerging it in water for 24 hours, and it does not leak, yet the tiny pores in gore-tex allow water vapour to pass through quite easily. Just my 2¢.
In a general sense yes. But consider this....Your feet contain about 250,000 sweat glands, which can produce as much as 1 cup of moisture a day. Not everybody but, in some cases. I go back to my original point cream polish is better for your shoe and foot. That's all I'm saying.