There could be more wrong theories about the universe than there are currently known galaxies in it.
We currently have almost no idea of which is formed and most importantly of the laws that govern it. We are still far away from knowing whether time or space are emergent or fundamental.
Even a Black Hole could hold an entire Universe just like ours in it and we'll never be aware.
To close this, my theory is that the Universe is some big brain and the galaxies are just some kind of neurons. We're all parasites.
