Don't understand. As long as there are devices that rely on Lightning, those cables won't get scrapped. Lightning cables normally fail during the lifecycle of an iPad or iPhone.Having hundreds of millions of cables hit the garbage dump Is not shortsighted thinking, it seems like a legitimate issue. You can rehash or not; makes no difference.
So what exactly should cause a Problem? If I would buy a new iPhone with USB-C I wouldn't buy another USB-C cable since moste devices already use USB-C (starting with the Macbook, iPad Pro, GoPro, Wahoo Elemnt - to name only a few).
If the old Lightning cable ist still alive and kicking, it will be sold together with the phone.
So where exactly do you see "hundreds of millions of cables hit the garbage"?