Maybe because republicans spent generations claiming the government can’t and shouldn’t do anything.

Can't speak to the world as a whole but the US has we spent 50 years gutting most government functions that aren't part of the police/military/surveillance apparatus (and many of those as well). SpaceX itself is an example of the primary mechanism of this: Diverting funding to private, no-bid contracts that remove both market forces and democratic oversight from those services while also ballooning their costs

Once you notice the pattern of how these companies are started you will see that there is a hidden hand of government behind much of what we think is an independent, market driven, capitalistic enterprise. Whether it’s Facebook or Oracle or Palantir or SpaceX it’s all the same. Heck even the founding of Silicon Valley itself can be viewed to be government driven. The bottom line is national security is not going to be left to the whims of a market when the pentagon has a black budget that can eclipse all of VC spending with the stroke of a generals pen.

> Why didn't the government try...

As a broad generality, governments are utter crap at inventing/building/operating bleeding-edge technologies at giga-scale. Exceptions are generally narrow-focus military hardware, plus flood control, aqueducts, and other "obviously needed for the nation's welfare" stuff.