The cheapish mp3 players of that era had barely enough power to drive a pair of in-ear earphones. If you ised a pair of over-ear ones, you would get hardly any base at all.

I kind of hoped there could be a Miles Davis one shaped like a 3D head blowing a trumpet, for example.

Or that Weird Al would release ones shaped like (a cartoonish version of) himself with the headphone plug located between his butt cheeks.