4,000 nm range isn't enough against the winds. Effective range becomes 500-1000 nm less into the wind.
It needs 4,500 - 5,000 nm range. That would give you 4,000 nm range into the wind.
Just checked a 4,600 nm leg. 767-300 restricted to 180 passengers with a close alternate due to winter winds. Published range of 6,000 nm weight restricted on a 4,600 nm leg into the winds.
Udvar-Hazy has complained about the lack of suitable a/c for the 3,000-5,000 mile markets and that the 787-8 and A350 are too heavy for those mission profiles.