It is a lot easier to build something that will work perfectly once, than to make something that can be used over and over again, with only periodic maintenance. The maintenance on the shuttle wound up so complex and expensive it might have been cheaper in the long run to build a disposable, one-shot space plane, instead. It wasn't planned that way, but its the way it turned out.

It stands to reason that some maintainable but reusable system is the way to go, but it is difficult to design something like this from scratch. The airline industry has done it successfully, but they've had over half a century of development experience to come up with the technology, organization and the procedures, and much of that has evolved as a response to government regulation. The modern airliner and its supporting systems are a triumph of performance, safety, efficiency and complexity, but it didn't just appear overnight. What you see flying through the air is not just a clever machine, but the tip of an iceberg, a huge management and planning infrastructure that supports it. And every step in that management pyramid has been evolving slowly since commercial aviation first began, back in the 1930s.