A lot of these discussions just focus on the technical attributes rather than the commercial ones of how much the aircraft will cost to build, sell and operate, and how many will be sold. The 757, whose demise seems regularly questioned, was given up because customers stopped buying it. The 787 may look attractive but is very expensive to buy, and orders in recent times for that too have dropped off.
It does seem that, in the race to provide ever longer ranges, manufacturers lose sight of the shorter ones where the bulk of traffic actually is. In their quest to do Sydney to New York nonstop in starts to put in features which make London to New York or Dubai less economic.