Mandated by Congress.
The explicit reason for this was that parts of the space shuttle were built in 50 states, and the “economic stimulus” trumped things like science or national security.
Yes[1].
You're talking about the how of the space shuttle construction but not the why. It was indeed intended for at least some military use, and it was originally intended to be capable of polar orbits and would've launched from Vandenberg.
Of course there was major government pork and horse trading to southern states but this was a side effect of the project, not the primary driver.
[1] https://space.stackexchange.com/questions/1398/did-the-space...
For example, NASA's original space plane was a much better design that the shuttle, but they were forced to make it a joint project with the Air Force to get budget. The different requirements added up, and eventually we got the system we've all seen.
A: I am not convinced GOOD science and GOOD engineering means a quick turn around. So in my opinion having less quantity for higher quality output is efficient.
B: While there are many missions and projects at NASA it seems a bit unfair to judge their workings when they seem to have major changes in direction every 4-8 years mandated upon them.
Edit: I understand that The Space Shuttle Decision by T. A. Heppenheimer [2] contains a lot of the information that's in the Metafilter post, but in a more sober tone. The PDF is available direct from NASA [2]. It does at least mention that NASA itself wanted to cancel the shuttle program.
[1] https://www.metafilter.com/48654/Jan-28-1986#1189388
[2] https://www.nasa.gov/wp-content/uploads/2023/04/sp-4221.pdf