Its a progressive degradation, similar to that of a light bulb Also, your test was probably in free air. The ratings on the wire are for it to be safe while in a wall packed with insulation. Any self-heating of the wire is going to stay by the wire there.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.