It would be great to have some actual numbers. How did reuse work out for Falcon 9? How much does the reused boosters for SLS cost? What's the cost and performance of an expendable Starship vs SLS?
It's not possible to compare, because while the SLS just got back from the Moon and is about to go back; SpaceX has never had a single successful super-heavy launch. Now that Elon has officially given up on Mars and decided to spend the next decade trying to figure out how to get to the moon, we may see some progress. All he has to do is put down the drugs and catch up to the NASA of the 1960s.