Not to be pedantic but your referencing of GM204 as midrange is wrong. 980GTX is infact NVidia's flagship product. People looking at paper specs and saying it is midrange purely on its bus width is just a case of the blind following the blind.
Its only the flagship as they didnt need to release the bigger maxwell chip to compete yet, just like the GTX 680. The 680 gk104 was the flagship for a while, then when the big kepler chips came out (Titan/780/780ti etc) it took its rightful place in the mid range. The same will happen with the GM204 980.