Sunamer,
The requirement back then (for the 747) was to move a lot of people around to a greater distance than the 707. The requirement for the 787 was to have a great fuel efficiency. The difficulties were similar.
Back when the 787 was running in difficulties I firmly believed that Boeing paid for its effort to kill two birds with one stone - new construction materials (and techniques) and bring a number or partners in a new base bearing full responsibility for their final input.