The Space Station and a method for bringing astronauts, cargo, and station modules to it, did not have to cost anywhere near what it did.

Remember, NASA is designed to do cutting edge research and development. That's their hammer, and every space application is the nail. The words "off the shelf" are anathema.

It's horribly ironic that NASA is now backing its way into a space transportation system that is very similar to what it would have had if they had simply extrapolated from the expendable launch systems of the late 1960s. The Saturn 5, already developed and operational by 1969, cost something over 2 billion per launch in today's dollars, including fixed costs. It's only function would have been large module launches and deep space heavy probes. Cargo and passengers could have been handled by smaller expendables, or a Dyna-Soar type spaceplane much smaller than the Shuttle launched on existing ELVs.

The Saturn had a good upgrade path, with designs on the board for reusability of even the S-4 stage. Never mind advanced electronics and other tech.

There are a lot of details, and some oversimplification of course, but the gist of it was that we had everything we needed to build and support a space station a long time ago.

Compare that to the money we've spent on ISS and Shuttle combined.