Every developer with a USB-C hub, an external monitor, and a drawer full of identical-looking cables has been here. You plug in a cable expecting Thunderbolt speeds or 4K output, and you get... USB 2.0. Or no video at all. The cable looks fine. The port looks fine. You start questioning reality. The problem isn't your Mac. It's that USB-C is a connector shape, not a capability promise. And macOS actually knows what your cables can do — it just buries that information where you'd never think to look. The Root Cause: USB-C Is a Mess (By Design) USB-C the physical connector can carry wildly different protocols depending on the cable: USB 2.0 — 480 Mbps, the bare minimum USB 3.0/3.1/3.2 — various speeds up to 20 Gbps Thunderbolt 3/4 — up to 40 Gbps, can carry DisplayPort USB4 — up to 40 Gbps (or 80 Gbps with USB4 v2) A cheap charging cable and a $50 Thunderbolt 4 cable use the same connector. There's no visual difference.…