Its not that people cba to look up there class and be good at there class its the fact most people my age and people i know cant keep to hardcore raiding schedules and revolve there lives around a game.
Now of course there is exceptions to the rule i know hardcore raiders who work harder than me and still can fit in hard core progression but they are few and far between and certainly not what blizz can bank on for future financial stability.
Bottom line is the huge majority of the player base is casual and if you cant keep them entertained then you will soon be out of business and its as simple as that.