History seems to indicate that, in the end, the airports adapt to the aircraft rather than vice versa. Maybe apocryphal but legend had it that on instruction from BOAC Vickers designed the VC10 with a big high-lift wing and lots of power in order to operate into short runways at high elevations in east Africa. Boeing and Douglas, meanwhile, designed the 707/DC8 to meet the majority of major airport runway lengths and consequently gave their aircraft better economics than the VC10. Of course, in time, the east African airports just extended their runways in order to accommodate the 707and DC8 and the rest, as they say, is history (Super VC10 notwithstanding).
Given that the 777X is 8 -10 years away from service entry, I suspect the airports have enough time make adjustments to accommodate "hingeless" aircraft.