USB-C cables are physically identical but electrically incompatible, causing silent performance degradation

Two USB-C cables can look completely identical — same connector shape, same plug dimensions, same color — but one may support only USB 2.0 at 480 Mbps and 15W charging, while another supports Thunderbolt 4 at 40 Gbps and 240W charging. There is no reliable way to determine a cable's capabilities by visual inspection. So what? A photographer plugs an external NVMe SSD into their laptop with the wrong USB-C cable and gets 40 MB/s instead of 1,000 MB/s, turning a 2-minute file transfer into a 50-minute wait — but they blame the SSD or the laptop, not the cable. So what? They waste hours troubleshooting the wrong component, reinstalling drivers, or returning perfectly functional hardware. So what? Across millions of users, this generates enormous volumes of false-negative product reviews and unwarranted returns — Anker, CalDigit, and other peripheral makers report that cable mismatch is a top driver of support tickets. So what? Manufacturers raise prices to absorb the return/support costs, and consumers lose trust in USB-C as a standard. So what? The promise of USB-C as a universal connector — which the EU literally mandated — is undermined, fragmenting the ecosystem back toward proprietary solutions. This persists because the USB Implementers Forum allowed wildly different electrical specifications (USB 2.0, 3.2 Gen 1, Gen 2, Gen 2x2, Thunderbolt 3, 4, 5) to share the same physical connector without requiring clear, standardized labeling on the cable itself. High-wattage cables require an internal eMarker chip, but nothing prevents a cable without one from being plugged in — it just silently underperforms.