Re: "given that the rocket is lost during the test anyway?"
Historically, that is called the "Military-Industrial Complex". It was a thing that President Dwight Eisenhower warned about. When the same small groups always deal with each other, and the players change sides sometimes, well, things happen that might not be strictly legal or even vaguely ethical.
Rocket purchase by US Government agencies is like that.
Space X is an outsider to the Good Ole Boy system at NASA and the Military. They compete on cost, which is why they run the largest single percentage of non-governmental launches worldwide.
That said, don't expect to see many changes in NASA's way of doing things. NASA has always been a "Cost is no bother" shop. That is understandable, as their actual mandate is to advance the technology. Maybe it's time to pass off the ISS to the Military. They generally do these things with only a hundred percent cost overrun.
Biting the hand that feeds IT
