A single key of my 2017 13” MBP failed, and the culprit turned out to be the black paint that helps the backlight diffuse more evenly throughout the keytop. It was the paint that had flaked off and jammed the key rather than any external dust. So look to the formulation of the black paint and its adherence to the type of plastic as an element in this problem. It appears that the plastic flexes when you press the key, and if the paint adherence is poor or the paint is too rigid, there is a non-zero chance it will break off and float around, causing trouble.
The spring mechanism to tension the flat cable is probably to stop it kinking as it slides in and out of the slot in the base. This makes it a “pull” when moving in both directions, rather than a “pull” on open and “push” on close. A kink might stop the display closing, and would probably ruin the cable.
Bad news. I have one of these, and after 18 months the display has failed due to the ribbon cable/flexible PCB going open circuit. The bend radius on the flex-PCB is about 2.5 mm, which is pretty small for long term durability, even if the thickness and materials of the PCB are optimal. (Dynamic flex-PCB designs typically use a radius of 5-15 mm for long life.) In contrast, my old Apple laptops (10+ years old) haven’t suffered from this sort of problem, so it’s not clear to me that this change is actually an improvement and not another step backwards in the pursuit of thinness.