A thought:
Just as history (by Hugo’s understanding) marches towards the end of history, and just as the goal of revolution is to end revolutions,
Les Misérables is a work that hopes for its own irrelevance. Hugo predicted in the introduction that the story would continue to speak to people around the world for as long as physical and spiritual suffering persist. History hasn’t yet proven him wrong on that point – but by his own ethic, that’s a bad thing.
Most literary works hope for immortality, but Les Misérables works for its own erasure from society.
The effacement, if it ever comes (from progress and not forgetfulness), will be a fulfillment.
It’s written in chalk, just like Valjean’s gravestone. But here we are, still waiting for the rain that will wash it away.