Starship has not yet flown even a fraction of what SLS has, so I think the comparison is premature. If it takes another ten years to get to a point that it can successfully achieve its Artemis objectives, I doubt it will remain cheaper than SLS. And given that it has already been delayed way beyond the first estimates for when it might be ready (it was supposed to have flown to Mars with astronauts on board by 2022, I believe), I don't see why another 10 years is any worse an estimate than others.
replySLS has flown once. What are you talking about?
reply> the capabilities are so far mostly just talk
replylol what? They've caught and successfully reflown the super heavy booster, and they've mostly successfully done a soft landing of Starship in the sea. How is that remotely "just talk"?
As mentioned elsewhere in this thread, things like delivering a real payload or orbiting the earth.
replyYes they've reflown a caught rocket, and they've soft landed in the ocean. I can do those things with a paper airplane.