Notice in the in the book the Last Battle, everything that was good in the old Narnia is in the new Narnia except the lamppost.
I was thinking, maybe this alludes to the fact that in the bible, it says that there will be no sun in the new heavan for God will everyone's light. If the lampost represents light, then in the new Narnia, it would not be needed for Aslan (spiritual light as Christ is) would be there.