In Gatsby in the valley of ashes, why is it only "with a transcendent effort" the ashes take the form of men?

To "transcend" means to "go beyond" or "rise above". In that context, he says that it takes an extra or extraordinary effort for the men working the ash heaps to be seen as actual men. This might imply that the men working the ash heaps are not much better than the ash itself - shells of men beaten down by life and labor who must will themselves every day to continue the effort of dumping ash on the ash heap. Note: This is my opinion - the author doesn't explain the phrase directly.