If I drive to Santa Fe, the town stays put while I get closer and closer. Moral progress is different. A good part of the moral journey involves the recession of the destination. This morning I discovered that C. S. Lewis had had a similar thought.
"No man knows how bad he is until he tries very hard to be good." (Mere Christianity, 124)
Allowance made for a bit of exaggeration, our moral predicament is describable as Tantalusian. Remember your Greek mythology?
Tantalus (Ancient Greek: Τάνταλος Tántalos), also called Atys, was a Greek mythological figure, most famous for his punishment in Tartarus: for trying to trick the gods into eating his son, he was made to stand in a pool of water beneath a fruit tree with low branches, with the fruit ever eluding his grasp, and the water always receding before he could take a drink. (Wikipedia)
Something of a stretch, but a tantalizing conceit that I couldn't resist.