At least the modern lightning and USB-C cables can be replaced easily and cheaply. In the bad old day of MagSafe, a cable failure meant replacing the entire charger.

As for Apple's recent cables, the rubber has become discoloured on my very-well-used 2017 MacBook Pro USB-C charging cable, but it's still completely intact with no signs of fraying or failing. My ~2.5 year old USB-C to lightning cable seems to be holding up well so far too.