Actually, I have the same problem. I think that after many years the cable jacket starts to lose its properties in the places where it has been touching the skin. Certainly, you shouldn't send your headphones to Germany. It is very easy to disassemble them - there are just three screws behind the pads and the foam filter. Anyone with very little skill can replace the cable. With regards to making the cable detachable, you can do that but only using those tiny horrible MMCX connectors. Anything bigger won't fit, unfortunately.
Yes, true. MMCX was my first imagination came up in my mind, too. But find it may a bit difficult to solder the wire to the junction, after search some picture of how to bond the mmcx socket. Since it is design for tiny antenna or in ear elements. The common 3.5mm two pole socket is too long and big for it unless special design one is found.
to follow up the case. I have made a modification of the debris (cable) by cut the cable at the joint. that is to let the two cups and its cable free. and then use heat shrink sleeve as the sheath. Each cable contains 2 wires. White and green for the left while red and green for the right cup. From an online supplier, I have bought a 4 poles 3.5mm socket. solder the 4 wires according to the balance cable configuration. From now on, I can use it depends on either an attachable balanced cable or unbalanced cable. Problem solved.
