If USB cables failed to transmit audio data uncorrupted would the result be -
A - poorer sound quality
B - the sound cutting out, crackles, pops
as the signal has not arrived as it should be?
I think the answer is B as how could corrupted data affect clarity, bass, treble as that would suggest the error is only one part and consistently one part of the data stream. Any corruption would affect the whole signal either for a short period of time, so possibly causing a crackle, or longer so cutting out the sound altogether.
B is the obvious and logically correct answer. Error are random. In a digital system, the signal is a word that's 16 bit long. Consider this, if you say the noise is lower, this means the error will occur only at the LSB. If you say you have better high, this mean the cable will have to create a new value (word) at certain high frequency and have to have explicitly corresponding value because too large or too low will create a pop and click noise instead.
One other factor to consider. Unlike analog cable, USB cable actually has a standard. This means the cable companies and the USB community worked together to engineer a specification. As long as the cable meets the specification, the USB will work. If anyone has a better cable, they can make a proposal to change this standard. Imagine the money you'll make if you actually have a superior technology in this USB cable. There are over a Billion USB device shipped per year. If you only make one dollar each, you still make a billion dollar. So just from the economic alone, a $1200 dcable does not make sense.