I have never been able to understand houses with internal gutterings

What I cant understand is how you can ever build a house with internal gutterings and not expect that one day , sooner or later , that the guttering will leak --- and where does the water go ? Not outside , but down inside the wall where it must get trapped because of all this modern stuff that doesnt allow the cavity to breathe --- result , a damp mouldy house and rotting timbers, especially in the area of the inside of the external walls
Is my thinking on this correct ? It seems pretty straight foward and logical to me
Regardless I would never buy a house with internal gutterings

As others have mentioned , the old houses with adequate eaves and walls that can breathe cope remarkably well

I am not a builder but in my humble opinion changing the old tried and true methods , for whatever reason , has been the major contributor to the current problems