As the early universe expanded, dark matter clumps formed. However, the dark matter didn’t expand as quickly as the universe, leaving a sprawling cosmic web of dark matter strands and filaments behind. The intense gravity within the filaments dragged in normal matter, which built up, then collapsed to form galaxies. The dark matter acts as a scaffolding for all matter. The thicker filaments create galaxy clusters. Dark matter may have even created the atoms.

My thoughts:

It’s known that galaxies flow along dark matter filaments in super-structures such as the Sloan Great Wall, and the BOSS Great Wall, so it must be that dark matter itself is flowing, possibly in different directions in the same filament, which creates a whirlpool effect, making the galaxies spin. If so, it must be a consistent flow of dark matter, or the galaxies would change speed and direction.