It's not like SLS is on schedule either, and it is absurdly more expensive than Starship. It's very likely that Starship will eventually be operational with lower total costs by any accounting measure. (And I say this as a current NASA contractor and current anti-fan of Musk)
We have no idea what starship has cost. It's a private company.
I agree that SLS is not an efficient project by any stretch of the imagination, and they have their own problems. I don't really see a reason to believe that Starship will ever achieve the goals that were declared for it. In particular, their plan for how to achieve the Moon mission, requiring an unclear number of missions to fuel a single flight in orbit.