Einstein added his term for the cosmological constant to account for the vacuum pressure in the universe that allowed it to be a static no-changing universe. With no vacuum pressure the gravitational force of the universe would implode upon itself and recreate the singularity from which it all came.
When Hubble found our universe was expanding and then others that our universe was accelerating in its expansion, dark energy was conceived of to account for the imbalanced Einstein Field Equations.
When the universe was described from a large scale, that is was arranged in large filaments that lacked the gravitational force to account for the very arrangement of the filaments, dark matter was conceived of to be hiding in the massless voids in between the filaments.
Perhaps it was not a Big Bang, but a singularity that, like a reverse Blackhole, created and continues to create our universe. It was not a one time event but like a Blackhole it continues to pull in mass-energy from outside of our universe. Blackholes in our universe, allow things to escape our universe and pull mass-energy out with it continually.
The Big Bang is more like the big reverse blackhole that sucks Stuff into our universe and Blackholes are like vents taking stuff out. In this way things expand naturally without any dark stuff and Galaxies arrange themselves as they are by the force of the linear expansion outward between inward jest (Big Bang singularity) and outwards jets (Blackholes).
This is in line with life and growth. New Stuff always coming and old stuff always going out. Once the energy is spent creating things, like supernovas, they implode and create Blackholes so new life and matter can exist.