Tolik your post has many truth and facts. The U. S. has tested many weapons but not all. The great point you made is that the U. S., Russia or China have not won any wars in many years and if war happens with North Korea there are many questions to be answered. Will China get into the war? Will Russia sit there and not get into the war. Will the South Korea want to take over the North? And will Japan get into the war? Many questions.
But I believe this war will happen this time around.