A
wooden peg is someone who's greatest claim to fame is that someone planted a seed for him to exist.
Wooden peg's were never to become great oaks; they are cut down to size, hold tight for a while only to suffer more humiliation and drop to the ground, often into a freshly laid
dog turd.
A wooden peg is the sort of person who will end up with the wooden spoon award.
A wooden peg could be having a run of luck, such as holding onto some sweet model's lingerie but everyone knows it won't last because the person is a dead set loser about to fall again.