I had a plant just like yours. Kept it for four years. Gave it fertilizer, changed light intensity, repotted, even withheld water at one point (it just got soft). Anyway one day it just up and died. I wish I had grafted something onto it. I suspect that without a a growing point it just acted like a root with the top part making just enough chlorophyll to keep it alive. Kind of like rooted Hoya kerrii leaves that they sell on Valentine's Day. No chance of putting out new growth.
