I'd start then by stating what music you listen to. Recording quality varies wildly, with the worst music highly compressed and distorted and the best having huge dynamic range, glorious sound and being mastered extremely well.
One of the first bands I loved was Van Halen. The first record of my own was OU812. I eventually got it on CD hoping the sound quality would be better, but, honestly, the recording quality of the early albums is pretty dismal. Now I listen to a lot of jazz and classical (a funny kind of full circle for me as my father listened only to classical music). In these genres I very much appreciate the subtle details, so I have an expensive system. Van Halen has been relegated to the car stereo. I am currently listening to one of the best jazz recordings ever made (Bill Evans Village Vanguard Tapes) but on a DAC/amp that costs <$300! The good thing is, for various reasons the electronics available have improved considerably, especially with regards to digital input quality and you can get cheap, but very low-distortion and high-quality gear.
I deleted the quote about USB cables by accident, but I think that USB cables became a big deal when people started using computers as digital transports. Early USB implementations had high jitter and other issues, so at the same time people started working on better solutions for using a computer as a transport (eg: async chips etc.) to the point now that any benefits a better USB cable might have brought have been made redundant.
So, the earlier issues were issues within the digital domain? (eg jitter) That makes much more sense than the USB cable affecting the encoded music signal.
USB receivers are far better than they were. A few years ago it was pretty much just the BB PCM2706/2707 for USB. Now we have the custom TAS1020B async options, the C-Media and Tenor chips, including their latest async one and other options I've forgotten. Along with keeping noise from the computer out of the circuit, there is also far more focus on good digital implementations with very low jitter.
I reckon it hasn't been as much as case of computer-as-a-transport gear being overpriced, more so that the ability to make cheap but high-quality digital gear has become easier, as the chips in all of those didn't exist a few years ago, from the DACs through to the OPAMPs (if any). So I don't reckon it is a big surprise that the ODAC/O2, NFB-16, Dragonfly and anything else similar can exist, but more so that computer- or DAP-transported digital has come of age.