i see the reason for a car’s brakes - to heat treat the rotors evenly and burnish an set the pads, but I have never seen any explanation for speaker cables.
I think one of the reason is with real world objects such as car brakes, you can see it with your own eyes. With electrons and molecular structure, it's hard for people to see or understand how things work at that scale therefore one has to have some back ground in electrical engineering.
Imagine a molecule and a billiard ball. The difference is the billiard ball is composed of many molecule, but the molecule moves and disturbed in just about the same way as a billiard ball. But most people probably can't visualize a molecule because visually you cannot see a molecule therefore it seems somewhat mysterious. The billiard ball and molecule are both governed by the same principle: F = ma.
Once you could see how molecule, electrons and their behaviors are not that different from a billiard ball, then maybe you could understand the effect of break-in.