Of course, the answer to why it is done, is the money flowing into many states involved in the production. Jobs are something every politician likes to create.

Of course, the answer to why it is done, is the money flowing into many states involved in the production. Jobs are something every politician likes to create. And it is part of an economy, that the state spends some amount of the tax dollars to support a wide range and healthy economy. But for that, the jobs need to do something useful. Just overpaying for rocket engine is the quite opposite. The same amount of money could be spent to create jobs which have a longtime value and as a consequence create more jobs. Even if it was just used to accellerate the whole project by not wasting effort on something which can be bought at a fraction. Like in having the funds to make a real moon station, instead of creating a rocket, which goes to the moon once or twice and then gets cancelled because at those costs, you cannot afford a moon station.