As someone who worked for NASA, I can tell you all those spin out numbers are bunk. NASA is indeed a good investment, but not for the reasons given. NASA public relations has cooked the books.

These analyses are highly questionable. NASA has a long reputation of being highly inefficient for good reasons. SpaceX did a much better job at optimizing cost in a way that NASA never could have, so it raises the obvious point: how much better would ROI have been in a world where private spaceflight was incentivized earlier? The answer isn't obviously in NASA's favour.

It’s hard to say privatization earlier would have lead to better outcomes. The drawback of privatization is the constant search for profitability which puts undue pressure against safety (Boeing?). Historically, only nation states had the organizational structure and long-term thinking to fund the massive investment required to research space flight in the first place, often motivated by weapons development.

Obviously, this is no longer the case. However, It’s arguably because of these nation-sponsored programs that made companies like SpaceX commercializable in the first place since they’re piggybacking on a lot of the science done by the governments.