That isn't the point under discussion. You claimed the US could see everything NK was up to. They cannot. They cannot even see below the surface of a roof. But even if they could, they don't have the manpower to do so. But even if they could watch everyone meaningful in NK at once, they'd still only learn so much from observing overhead.
Depends what wavelength they are looking in. UV or IR will be able to see through a roof. But it won't be cystal clear.
They will have been watching all movement in and around NK military facilities for years. Not just with satellites.