Well the other ass-sumption was that the cable worked before and so was up to specs until it wasn't.
And I'll see your USB 3.x and raise you an HDMI+USB KVM switch: I'm returning my 4th one and this one's a record setter: it came with USB (v.2) ports DOA. In all the others it was HDMI and it took them a couple of weeks to go titsup. One lasted the whooping! two months, even.
Lol. Cables DO fail. I spent a number of years as part of the USB-IF compliance effort that was driven by Intel. My experience as an engineer on USB technology is a bit more than yours as a consumer.
if you want more reliable docking stations, I recommend Plugable. The founder used to be the dev manager for the USB team at Microsoft.
There’s a lot of crap out there that hasn’t gone through much, if any of validation.