There are people who simply do not play MMO's for the heavy handed side of pushing themselves. It isn't a "Sadly" moment either. Not everyone is interested in end game, they play for the relaxation and sometimes, they do reach end-game but that doesn't change their outlook. I will say that some people change mindsets at max level. The moment you are in 24 man CT and you see the fact everyone works together in some ways tends to spike people a bit. Other times, the mechanics of their class and how you max DPS becomes a mindset too. It all comes down to how they want to play the game.

That being said, i find some players attitudes towards people who are not "On their level" kinda scummy. Just because someone isn't max DPS all the time, doesn't mean they are any worse off really. As has been said above, there will always be a imbalance. You just have to get that it's different for each person.