Comparing the SLS program to SpaceX with their multiple vehicles in progress and constant updates to the systems, seems to prove that the people pushing for mor

Comparing the SLS program to SpaceX with their multiple vehicles in progress and constant updates to the systems, seems to prove that the people pushing for more private space industry were completely right. It seems though that having multiple component vendors should be advantageous. Is there any company working on that premise of integrating systems from multiple vendors? Because somehow it's not working out economically with NASA. Seems like we are still in early days, with a lot of the money wrapped up in bloated contracts for oversized military companies.