We're not just talking about a random wire through a cable at this point. Transmitting multi-gigahertz signals through a copper conductor is complicated. These

We're not just talking about a random wire through a cable at this point. Transmitting multi-gigahertz signals through a copper conductor is complicated. These types of signals are extremely vulnerable to the impedance of the cable, capacitive losses, etc. Producing a cable that stays in spec over some large arbitrary length while taking the abuse of being wiggled around all the time is expensive.