it is true that some of the more sound-conscious artists out there at least used to do things like create mixes for radio and mixes for cd/lp. you'll also find tv mixes back in the mtv/muchmusic days, and i've heard of corporate rock musicians mixing for mp3 (that was even really what the loudness wars were actually about). so, don't take my statements too broadly....

but, generally speaking, if an artist is marketed for radio play then the product that you buy on a physical media in the store is mixed to play on am radio, and plugging it into an expensive sound system is pointless because the source is intentionally garbage.

then, when you compress it it doesn't matter - because it's shit to begin with.

that is why people can't tell the difference - because they're listening to trash.