I use my cables as well, and I use them a lot. I have around 16 devices which I have to constantly charge around the house.
I throw the cables in my briefcase, backpack, pocket etc. I have cables which live in my car exposed to UV light but none have never degraded to the level shown in your photos.
My Apple In Ear Headphones do experience a lot of wear and tear to the point where I need to replace them, but even they have not gone to the point where the wires under the protective coating have been exposed.