Dave I know you have a superior knowledge of many things, but to say your insiders at Boeing foresaw the 787 as a 767 replacement just doesn't match the design of the new airplane. While true it is capable of doing the 767 flying the times, routes and design are entirely different. And you forget it is almost as fast as the 747 (slightly faster than the 777) which is an international/global feature, not domestic.
When the 767 was built the market needed a smaller two aisle two engine transcon, and major business market airplane. Boeing built the newest tech airplane of the day, the 767.
Today's 787 cabin is wider 18' compared to 15.5" (777 and 747 19+') and hasthe range to fly the expanded ETOPS circles. From the beginning CAL (and who really knows what Tilton was planning, besides his cash out when the merger was complete) bought the airplane to fly these long routes.
To say the improved fuel efficiency was a "bonus" really again is on the verge of either "alternative facts" or just down right grabbing ideas from the sky.
The biggest problem with the 787 is the difficulties Boeing had(s) with the design and new tech it has incorporated.
The real question you all should be asking is does United, or any airline, need a smaller two aisle airplane (ie nearly three feet smaller)like the 767 in its fleet. However, the main thing we need as pilots is more seats up front (number of cockpits not jump seats) for us to get paid to staff and fly.