At the risk of being boring on the technical side, there are real problems with PCM when trying to up the word length. The DAC chip has to incorporate resistor values that start with a value and then halve the value for the next resistor, then halve that again, etc till the 24 bits are provided. Providing these resistor values accurately on a chip and those values staying stable over time and with changes in temperature is very expensive and not really achieved accurately in standard chips. Therefore there is distortion and noise created (called non-linearity). This is one of the downside problems of pushing PCM up to the 24/192 standard. Sony's SACD uses DSD, which avoids this problem but creates its own problems. Noteably dCs (Elgar, Purcell, Delius) uses a mixture of DSD and PCM (putting it crudely) to avoid the problems both have when you push either technology to its limit. Sure the technology you employ is important, but the way it is employed is still likely to be the big differentiator for a long time.