The collective unconscious consists of more than our collective shadow, however. It contains all the traits of which human beings aren't yet capable. If you enjoy science fiction, as I do, then imagine that one day hundreds or thousands of years from now, humans will be able to read each other's thoughts without speaking. If that is on our path, then right now that ability is in shadow for humans.
To say that that trait, or any other trait, is in the collective unconscious means that all humans have equal access to it. It won't matter, in other words, how you're educated or where you're born. You'll have the ability, or at least the ability to learn, to read another person's thoughts.
That's because the collective is really a source for everything humans can be. It ensures that every human being has access to Sovereign energy for acceptance and motivation, to Magician for learning and intuition, to Lover energy for connection and feeling, and to Warrior energy for accomplishment and boundaries.
Any one of us can send our roots down far enough to tap into the nourishment of that underground pool. When we do, we get something new we never had before. In fact, we get something new that no one ever had before. Because even if I experience the same archetypal energies you do, I'm having a unique experience of them because I'm a unique individual, with unique life experience, body, genetics, and so on.