If there's a tool that's unique in its kind, none other existing, it's going to be very expensive as it needs to withstand vibrations, high G's (liftoff) and temperature extremes (in space), thus it needs tests (would it be reasonable not to test it and thus save money and time?).
Also, without a timeline (like Kennedy's bet), engineers can save money by not emplimenting all the expenses needed now, however, it's going to impact later on and end up costing more as there precisely is no firm timetable. And when time passes, a better tool for the same function, is proposed; what do they do...accept it or ignore it?
It's really not easy or even possible to be certain about the reliability, usefulness of a tool that had never existed before; how can we be certain of its cost, beforehand?
Then there's the Russian approach...Very well known technology, with very little progress from time to time...and cheap Zemyorka's (Soyuz launchers).

Raoul