I don't think the OP suggested connetorising the headphone end as something the consumer should do, but rather as a suggestion to manufacturers. Many high-end headphones already have this, as it not only allows you to replace damaged cables easily, but also choose a cable length and type (straight or coiled?) that suits you. The ATH-M50x ships with three different cables, for example.
You know when I was young there was this whole profession of tv/radio repairmans. Swapping a headphone cable is exactly the sort of thing I imagine they would be perfectly fitted for doing.
But of course these days the whole concept of repairing things is completely bygone thing for most people, so yeah, maybe wireless headphones do make sense.