The United States couldn't do either of those with NASA's budget... And the SLS is not NASA's entire budget.

I believe that space exploration is an incredibly important national priority, even if only as a means of maintaining our space-related military capabilities. Anyone who believes the US can abandon space travel and still be secure against present and future global threats is just a goddamn clown.

But generally we shouldn't pay $2 for a bullet that we could buy elsewhere for $1. We could buy a lot more bullets if we bothered to try to contain our unit costs.

NASA is a pretty small budget item compared to national healthcare.