This is Walter M. Miller's “Crucifixus Etiam”.
Troffies are mentioned in the review below
Desperate to find some sort of meaning for the work he is doing, Manue goes to one of the “troffies” (for atrophy, the older workers who have given up any hope of returning to Earth), who explains it to him as a problem of overproduction and underconsumption:
“So, it’s either cut production or find an outlet. Mars is an outlet for surplus energies, manpower, money. Mars Project keeps money turning over, keeps everything turning over. Economist told me that. Said if the Project folded, surplus would pile up-big depression on Earth.”
Miller, Walter M. – “Crucifixus Etiam” (1953) - Doomsayer Press