It's not just listening fatigue from sound, but the pressure applied to the ear-lobes. I have used circum-aural headphones that I can use for hours upon hours since they were very comfortable (no pressure) and were not too bright or forward that they caused listening fatigue.

Yes, I have a pair of Grado S60 (supra-aural) which are by far my best sounding headphones, but I cannot use them for many hours on end for this reason, as loose as I try to set them, they eventually become uncomfortable.