Marginal at best. The Space Shuttle lofted 833 astronauts at a cost of $209 billion [1]. In 2013, NASA was paying Russia $70 million per astronaut for a Soyuz lift [2]. That comes to $58 billion in 2013 dollars. That leaves $151+ billion, ignoring inflation, to justify everything else the Shuttle did. $150+ billion is 10x SpaceX's lifetime capital expenditures. (It's about what NASA expects it will cost to put humans on Mars.)
At first, the Space Shuttle (conceived as a shuttle to an American space station, the latter never built) was an expensive way to low-earth orbit. After the ISS, the Space Shuttle became an expensive way to the ISS. It pioneered virtually nothing and nowhere and was better at nothing than any other craft.
It was not worthless. But for the cost we could have achieved vastly more. Opportunity cost is real; the Space Shuttle set spaceflight back at least a generation.
It's not fun to trash these programs. But over time, I've realized it's necessary. We cannot correct failures we refuse to recognize. The Space Shuttle's dismal ROI was a motivating factor behind the Bush administration's support of COTS [3]. Without that programme, SpaceX wouldn't be what it is today.
The Space Shuttle was remarkably well designed for orbital bombing missions, which is the only reason the Soviets felt compelled to build the Buran to reproduce its capabilities.
