I think you have that backwards.
You have that completely backwards. Analog cables are affected by build quality not digital cables. Between background nose and interference the better made the cable is the more clear the peaks and valleys in amplitude are. The difference is that in a poorly build analog cable, the minor variations in amplitude are lost and it only peaks up the larger peaks and valleys. Use the link below as an example. A "poor" cable might chop off some of the variability in the amplitude of complex sounds (sounds within other sound), but a "good" cable would keep the signal clean and pick up both the primary sound and the various inside the main wave. This doesn't apply to digital signals what so ever.
It is still possible to get interference with digital signals, but it is much less common and would require a fairly massive EM field like running your HDMI cable parallel with the main power line into your house or running it behind the circuit breakers.