Generally wings themselves don’t float unlike other smaller hollow sections. This is because the “wing spar” runs across each wing into the “cross spar” central section of the fuselage and into and across the other wing. This part is immensely strong, because it carries the whole of the planes mass (static + Dynamic), and if you have an impact big enough to rip the wings from the fuselage, the main spar tends to get “peeled” out of the wing sections, which results in massive internal damage to the fuel tanks, and hence generally a lack of buoyancy.
Of course, an impact at a certain speed and angle could foreseably just perfectly snap one wing off intact, but generally (in planes the size of the 777) doesn’t happen like that. It also needs to be enough of an impact to break the shear pins that hold the engines onto the wings otherwise their mass will sink the wing.
There is also a huge difference in impact profiles between the 3 main possible impact vectors.
1) high speed vertical dive (>6000ft/min) (pilot suicide. loss of control etc) Nose first, doing >400Kts KIAS = unlikely to be any big parts left
2) high speed “pancake” inpact (>4000ft/min) (like AF447, entered from a high altitude upset into a fully developed stall) = again, only really small bits left, bits like Vert Stabiliser survive because they are on the top side of the aircraft)
3) Relatively gentle and controlled ditching into sea (~1000ft/min)(Ethiopian 961) = a few big bits left, but even then the main fuselage breaks up
4) Perfect controlled ditching (MH370 into Hudson) A much smaller plane, into flat calm water, with a high experienced glider pilot at the controls. Proves you can do it, but shows how difficult it is to do without causing massive airframe damage.
Any which way, at this time, this, and pretty much everything we “know” about the loss of this 777 is just speculation……
