A key point here is that our brains don't work like computer hard drives. Our brains are a lot closer to how, in biology, a single cell stores the entire DNA "data" that's needed to replicate but just using a few base pairs.

We likely store information more in some type of loose graph structure, where we recall / "remember" something by re-creating links to that piece of information. There seems to be very very little "storage cost" for the billions of pieces of information we keep in our brains.