Well, for starters the filtering you are talking about is only for ADC, not DAC - so it's entirely independant of the virus.
Maybe true with a filter for ADC but I wasn't about that. I was about reconstruction that needs a lowpass to avoid the backfolding issue evil from digital domain.
Second of all - using a decimating input (sima-delta or whatever) gives you a really high bandwidth to start with, now you can filter that digitally or with an analogue filter - incidentally 96dB/octave wouldn't be a great effort. Analog Devices quote for one of their off the shelf AC'97 CODECs a pass band (+/- 0.09dB) of 0.4*fs (for 44.1kHz that's just shy of 18kHz) and a transition band from there up to 26kHz. (-74dB at the nyquist point - full scale sinusoids at just over nyquist point could only occupy last 4 bits, by the way thats over 150dB/octave, so the aliasing could only occupy 2 bits at best by the time you ramped up the frequency of the sinusoid so you could hear its aliasing). 48kHz makes aliasing disappear underneath quantization noise by the time it folds back into audiable territory - and this is with a full scale sinusoid, which would be unlikely to occur ever.
Not sure if you try making things much more complicated to cover that you are not so sure - or whatever?
I also didn't say it's impossible to get closer to what I showed up with as an example to make the basic effect clear - I just said you can't simply expect the theoretical limit the theorem promises... or a great construction from the two magic numbers.
Also, realtek, just because they quote 24/96 it doesnt mean you're actually getting that resolution - its like when they stick 12MP digital camera sensors in mobile phones, the lens instrumentation just doesnt have that kind of resolving power. BUT that's the standard sensor they are flogging, so they stick it in anyway because it's cheap (especially if you are sony and you are making millions of them).
Practical numbers are fun...
Oh, now you contradict yourself a way, referring to real hardware and "practical numbers", that's indeed funny.
I do not like to jump into the digital camera thing here - also there are some parallels - and some even more complicated other things ....