Probably why they break so damned much.
I’ve owned Apple chargers for about ten years. My second machine, the 2006 Macbook, was the only one whose charger ever frayed and broke on me, and it was completely due to my abuse of the thing. I’d roll over it with the wheels of my chair, yank it out from the wall, toss it in my bag, wrap it tightly, etc. the thing took such a beating that I’m surprised it lasted me eight months.
I’ve run through multiple chargers since then and I’ve never had an issue. I’ve started taking very good care of my chargers and have not run into a single incident since.