Another problem that the 787 shares with the Comet, is the reluctance to build a demonstrator and test it, before embarking upon production airframes.
Not since the days of the 707 has Boeing - or any other Large commercial aircraft company had the luxury or finances to build a ' one of " and fully test it BEFORE starting production. Its NOT like an auto assembly line !
For example - the 737 747 767 777 787 all had multiple planes in various stages of production( assembly line ) before the first one flew.
Thats why its a major gamble bringing out a really new model ( not a derivitive ) since the major tooling, assembly fixutures, sub contractors, etc have to be in place and IN production by the time the first one flies
Amoung the first 4 or 5, one goes to static test, one goes to fatigue test, two or three typically fly- and are later refurbished and sold
Boeing kept the first 707 and used it for flight test of a wide range of things, as in tanker, etc - it is now in aerospace museaum in wash dc.