The 787 was almost as bad as the F-35. Somewhat different problem, though. Theirs was the issue of too many subcontractors with subcontractors with subcontractors and poor control over manufacturing. They literally bought companies that made the parts because they:

1) didn't have the manufacturing means themselves;

2) couldn't control the quality enough via contract measures.

That significantly drove up the cost of the 787 project. Someone really needs to do a good write-up on these two projects as today's version of the Mythical Man Month and similar texts.

Keep in mind a 787 can carry 242 to 335 passengers. The first Booms are going to carry about 50. Significantly smaller plane.