One reason was Bill Gates bought the company that developed the chip and it then became more prohibitive for companies to include it in their playback machines.(for whatever reasons)
Why HDCD did not become a dominant format?
I've been listening to Reference Recordings 30th Anniversary Sampler while evaluating a Sony NS 9100ES and it was so obvious the HDCD decoding through my modest older Toshiba SD 9200 was "vastly" superior to the new Sony playback. I just don't understand why HDCD did not become the new standard as the musical quality is much enhanced. What happened?