[wtallis]

The critical difference is that USB versions keep adding new wires and active components, while the display cables largely stick to tightening the analog signal integrity requirements. Whether an old HDMI cable works for a new display is largely a question of how high the data rate is for the new resolution and refresh rate, vs how much the manufacturer of the cable overshot their analog bandwidth target.

[klempner]

USB hasn't added any active components or wires for short cables since USB C's introduction (which added emarkers and an extra pair of superspeed lanes for full featured cables)

All of the improvements in passive C cables since then are exactly the same "analog signal integrity requirements". Heck, the most common protocol for sending a display signal over USB C is literally just "send a DisplayPort signal over the superspeed lanes".

Now, USB C cables are more likely to have active retimers or redrivers in them, but a lot of that is that the highest speed signals are well above the display side. Even UHBR20/DP80 from a signaling standpoint is mostly just good old 40 gigabit Thunderbolt 3 except with everything pointed outwards (so 80 gigabit unidirectional instead of 40 gigabit bidirectional)

[Tharre]

No? Passive fully-featured USB-C cables had the same amount of wires and active components, which really is just the e-marker chip, since day one. The same 5 Gbps cable can now do 20 Gbps if the cable was made well enough.

Active cables are a different story of course, but that's the same for HDMI cables.

[wtallis]

I was including USB history before USB-C, because HDMI and DisplayPort have been around much longer than USB-C. And limiting the discussion to "fully-featured USB-C cables" is ignoring most of the real problems.