I made French Onion Soup the other week. In the end, it just made three big dinner-sized bowls of soup, but the recipe started with carmelizing 5 big onions!
Once that step is done, they must be a tenth of their original volume.
Probably some kind of metaphor there. Like things can feel so damn big in your head right when they are happening. But let them simmer for a while, they get a lot smaller.