The largely intact wings really present a puzzle. When we think of wings being pulled off by aerodynamic loads, and how relatively easy that is... "
The wing to wing spar /body joint is the strongest part of the aircraft (often called the wing box). It has to lift the entire weight of the aircraft plus maneuvering forces of up to 6 times that weight.
It will be the last thing to break. You will see the fuselage fall off and the wing ends fall off before any break in that part.