There is a progression in the foolishness of the fool, and it is not in the direction of what is good, but of what is harmful. This is true over a single conversation, and it is true over the course of his life.
As life goes on, he will show himself incapable of learning true wisdom no matter how old he becomes. Sin is like a progressive disease and it affects more and more of our nature. What little good there is in us at the beginning of life tends to get eroded away as we compromise more and more with the standards of conscience and find ways of getting round moral obstacles that blocked our ways in the past.
But if this is so, then it is futile for the fool to think that given more time he can correct himself, learn to do good, gradually improve his conduct until he comes to the point when he is acceptable to God. Something much more radical than he can imagine is called for, something that is completely beyond his power.