silly we all know it doesn't. But mp3's lack sound stage and the nuansaced details you get with Red book and 24/92 flacs
and honestly, when you start getting into the $1000 headphones, it's the sound stage you start paying for. I know the sound signiture that I enjoy, the differeance between my old DT 880 and HE 4 is mostly in sound stage and the generall texture of the music. Lossless to my ears sounds closed in, seeing as it has a 20k hrz shelf and lacks the "air" or white decay noise in the treble. Not only is this audible, but it's visuable in a spectrum analysis.
but again... buys a $1000 DAP...and uses it to listen to lossy... not a smart move ino, but as long as your enjoying it that's all that really matters.
I take it you've never conducted a fully blind abx between mp3 320 / aac 256 and lossless using the same source (transcoded properly) and volume matched correctly?
I'll give you a little tip - you can't actually hear anything above 20 kHz - so how could it be doing what you're suggesting.
Here - the software is free, all it takes is time - test yourself (http://www.head-fi.org/t/655879/setting-up-an-abx-test-simple-guide-to-ripping-tagging-transcoding)
You may find your whole outlook on this topic changes