Boguing,
I see where you're coming from. For a propeller, there is the rotational component, (in-plane with the disk) that increases in magnitude at a further-out radius; and the forward component, which is the same at all stations. The resultant of those two is the relative wind, which changes angle due to the change of the rotational component's magnitude. (Notice that so far, I have not brought the chordline into the picture. All we're concerned with, is the relative wind and the components that go into it. Without referencing the chordline, we understand the change in relative wind. But this changing relative wind is why the twisting chordline changes along with it, to keep AOA the same.)
But the analogy from this, doesn't carry. For the (wings of) the plane in a turn, there is no motion component analogous to the forward component of the prop. The plane is moving forward, of course, but THAT IS the rotational component. The whole picture is turned up 90 degrees. If you simplify it down to look at a plane doing a zero-bank turn with rudder only, different stations along the wing are moving at different speeds, but the direction does not change. It is precisely horizontal. There is no motion 90 degrees to that, to add and come up with a resultant at an angle.
If you remove the zero-bank simplification and look at a normal banked turn, the path of the wings sweeps out a cone instead of a disk, but the relative wind at each station still comes from the horizon...with no component from above or from below. Upon rereading your post, this could have been a lot more succinctly put to say "there is no vertical component." Anyway. There is no relative wind change, therefore there is no AOA change. (Of course most planes have washout that varies the AOA, but this is mirrored left vs right.)