Yes the money stays on Earth, despite that the news media always implies the opposite.
Why is it so much? Because it is not a space program, it's a congressional district jobs program where "progress" is irrelevant and accountability for lack of results is minimal.

We had SkyLab which was roomier and less expensive. We could have used shuttle external tanks as roomy building blocks or better yet some inflatables off a central metal core.

The mantra of Danger! will robinson, poor quality is often used to rationalize the obscene high costs. Meanwhile, our same society tolerates blithely numerous car racing and mountineering deaths.

30 years after the last Apollo moon mission. The better part of $100 Billion and we have a 3 person LEO space can which requires full time 3 person human janitorial care to stay operative, despite all our advances in computers and electronics. That's pitiful. SkyLab was more productive 25 years ago.