This effect does not exist in a quiet listening environment. You go to visit an audio shop. Walk up the stairs and they’ve got a listening room. No one else there but you and the sales guy.
Yes this "effect" does happen in quiet room. The ability to pick out relevant details in a noisy environment is just one outcome of how the brain adapts. Our hearing including our ability to extract details, hear artifacts, etc. is not static. It is task dependent. At a lay level, it is called selective attention. At a neural level, our brain rapidly adapts neural weighting to the tasks on hand, which means if you are looking for discrepancies in how you think something should sound, you are far more likely to hear them as opposed to them just being "background" information.
The process whereby you adapt to a new piece of equipment is also related. Initially it is new, so you are looking for artifacts, differences, changes. If there are really changes, you are more likely to find them, because your brain has rewired to actively look for them. It will also find things that were always there that you never noticed. Over time, you/your brain settles, and you are back to listening to the music.
mp3s are not great. Sure, you could fool someone in to thinking that 2 files are the same on a smartphone over bluetooth, but upon further inspection; in a more resolving system, you could tell the original .wav file and .mp3 file apart easily, no matter what the kbps was, even 320 kbps.
How confident are you that if presented with only an MP3 file, 320kbps, that you could accurately state that it is MP3?