"We can make the reasonable assumption that a media system is dealing with 16-bit 44.1 kHz stereo audio."
No, we cannot. Want to watch a DVD? Then you're dealing with 5.1 48KHz audio. DVD-Audio? Could be up to 192KHz. Blu-Ray? 7.1/5.1 and IIRC could be 96KHz. DVD-Video also allows 96KHz stereo.
And that's not even getting into stuff that's slightly less common than things almost everybody does at some point. (OK DVD-Audio doesn't really come up since there's no software players for it and pulseaudio currently caps it's sample rate at 96KHz so it has something to use as a maximum sample rate)