Yeah that's definitely a valid point about most people not really being able to tell teh difference.
It's not the DAC's that are lacking, those are at least 24/192 it's the internal processing that's the bottle neck i.e. matrix processing, Dirac, etc. the SP4's direct competition all have 24/96 with the Trinnov Altitude32 being the exception at 24/192 on I believe 24 channels and 24/96 on 32 channels. That means both the Theta Casablanca and Datasat LS10 which both are DSP based SSP's like the Bryston (vs PC Intel chips) are both able to achieve 24/92 and both the Datasat and Theta have Dirac like the Bryston.