"But how much does it really cost to rebuild an exact copy of a satellite "
That's actually a pretty good question.
In production engineering the term "learning curve" actually means what's the cost to double production. In combat aircraft (in WWII where this stuff started to be studied) it was about a 15% reduction per doubling. With more aircraft made in large single pieces in more automated ways it's less effective. However satellites remain highly labor intensive.
NASA had a classic case of this. IIRC the Voyagers were going to be a single probe but for various reasons they ended up building two. The second was significantly cheaper.
Biting the hand that feeds IT
