cstross , 
It's worth noting that the $6Bn cost overruns on SLS boosters and engines—the overruns ALONE—probably cost more than the entire SpaceX Starship program (for a fully reusable launcher with a much larger payload), currently running at an est. $2-3Bn/year total vs. $25Bn/year for SLS: https://techcrunch.com/2023/07/13/congress-prepares-to-continue-throwing-money-at-nasas-space-launch-system/