Consumers are absolutely brutal to cables. Minimum bend radius of copper cables get violated all the time, but copper has a decent chance of continuing to work if bent back. Not so with fiber. Fiber would only work with some heavy armor.
Consumer fiber was actually tried in the past: Optical TOSLINK was briefly popular in the audio world. It was cheap relative to what you’d need for modern high speed fiber, but even that was too much to win out over copper. It faded away.
Even within professionally maintained data centers, direct attach copper is often preferred over fiber interconnects when it’s possible to get away with it.
Fiber is great when called for, but copper wins in practicality when you can get away with it. It’s been proven over and over again across industries.
> Meanwhile, Apple wants $70 a pop for a single, 1m Thunderbolt 4 cable, and that's only been increasing.
You picked the absolute most expensive cable as your benchmark. Look anywhere else and prices are lower and decreasing.
Also, you are wrong about Apple cable prices increasing. They’ve actually dropped the price of their longer cables.
But again, look to the overall market and you’ll see prices going down.