Because the leveling and gearing content is boring, so we rush it. The endgame stuff is fun, but we want to get it down ASAP to show off. Then there's not enough endgame stuff to keep us entertained, but we still like the game and want to keep playing, we just now have time to play other stuff. So we pay our sub, log in twice a week and wait, what's your problem, why do you care what we do anyway?