So... if this is the case, then God is forbidden from revealing anything to mankind that is not already revealed in His word. He can reveal nothing of calculus, electricity, chemistry, nuclear science, internal medicine, mechanics, astronomy, or virology, and must watch His people suffer for lack of knowledge until they discover for themselves. He can't speak to people in dreams, visions, or any means other than His word. He can't even direct them to a particular passage of Scripture because that would be "inspired knowledge" outside of Scripture.
Hogwash. God is still in the revelation business. He just isn't adding to Scripture, because Scripture is complete for the purposes He gave it.