>>11417261Mainly three things IMO.
>NASA's distributed method of manufacturing and operationNASA has always strategically selected locations for their various facilities, not because it's practical or cheap, but because it gave them more favorable political standing. This resulted in development and maintenance cost being much higher than it should be, but it gave NASA the leverage to get a higher budget at the time.
>Shuttle's troubled developmentThe Shuttle was a kind of vehicle that was never done before, that'll make any development risky and unsure. However, during development, NASA took on massive budget cuts which strained the agency in making this vehicle. All of a sudden, not only was this going to be NASA's next launcher, but it's only launcher. It had to do everything NASA wanted to do in space, even if it meant a less efficient vehicle overall. To get more funding to actually properly finish the design, NASA had to sell it to the USAF and DOD who then requested changes to the design that ultimately drove up vehicle costs even further.
>Reluctance to upgradeWhile the Shuttle's design was flawed, what really damned it was that NASA never seriously perused upgrading it in any significant way. The RS-25's were marginally uprated, but never in a way to reduce the refurbishment time. The tiles were never simplified nor improved, so each Shuttle still had thousands of unique fragile tiles that each have to be inspected. The list goes on. It's not like the technology wasn't there. The X-33 displayed many technologies that could've been introduced to the Shuttle, but they weren't Why? It's complicated, but its most likely due to fear in NASA that Congress would just cancel the Shuttle if the agency seriously pushed for upgrades with no replacement.
One of these issues would've been bad for any project, all three made the worst launch vehicle in history. And there's much more detail that I'm missing.
