Factory-made CDs are duplicated by a physical process. Most bad CDs were made using an opto-chemical process. The chemical processes are pretty much reversible

Factory-made CDs are duplicated by a physical process. Most bad CDs were made using an opto-chemical process. The chemical processes are pretty much reversible, leading to dead CDs. The physical processes are much more robust, as you'd have to deform the actual base plastic, like cooking vinyl LPs in the sun.