personally i think the trouble lie in the community more than in the game.
most of the trouble come from the fact people are not patient anymore... if they don't get anything from it, they don't want to do it. worst they want to rush all.

i mostly play with a friend from america, while i'm french, we do a loooooot of DF at low, middle and end game. how we can't be burned out? simply by not doing always the same thing...
we need 8 amdapor for get capped... we don't do it all in one day, the max must be 2 time a day. the rest of the time we don't do the same stuff, we play another class (for get other skill or simply for extend our knowledge about the game) we do gathering, crafting, or simply talking.

people in end game don't do this (for most of them), they don't care, they are playing the game in the wrong way. most of them focus on one class or one type of class. after, they think they know how best the game must be played... and act all mighty and hard on first timer...

we was all noob at the start and some must remember this, instead to try to change the game... change yourself first.

anyway, with my friend we have seen the bad and the good from DF, but do we will stop to use it? never! the thrill to encounter people and beat a challenge with people we don't know is far stronger than beat a challenge with always the same people!