I read somewhere a company couldn’t duplicate the old F1 engines on the Saturn V but they offered and improved version which was smaller, easier to produce and had a substantial increase in thrust and of course NASA rejected it. They had government contractors to pay billions in over runs and for the SLS to be delivered decades late.
If the SLS flies they may can orbit the moon like Apollo 8, but they have no lander or even space suits ready for EVA’s. NASA has been in a death spiral since the Skylab program ended. NASA=government jobs program for bureaucrats.
It’s why SpaceX, Rocket Lab, Astra Space and a host of others are growing as NASA stagnates.