Two dimensional wings are always in ground effect, because they have the flow pattern of a three dimensional wing with infinite wingspan.
No, they are not always in ground effect. In free air they have the flow pattern of a three dimensional wing with infinite wingspan
in free air. Two dimensional wings placed near a ground board have different characteristics than when in free air.
No one is suggesting that studying the behaviour of 2D wings is going to help understanding of a 'real' wing, but looking at the flow on inboard sections of an Aspect Ratio 5 wing doesn't come into that category in my book.
The points to be made are (for a real AR 5 wing)
1. The upper surface flow is not much affected by ground proximity
2. The underwing flow develops steadily into a low velocity/ high pressure zone over most of the lower surface, from which comes the extra lift.
Wing tip vortices don't come into it - bound vorticity might be used to explain things, but I have learned that it doesn't pay to try to describe the flow to pilots in terms of bound vorticity!
Again I say they are meant to illustrate the sort of flow changes that occur near the ground. I assumed (and assume) that viewers would be able to interpolate for greater heights for themselves - it was anyway the only set of illustrations I could find at short notice.
In fairness I should also say that the illustrations were taken from a report discussing wings operating really close to the ground but, and I would emphasise this, the pressure distribution diagram and the general flow behaviour correspond closely to that observed on the AR 5 wing, which was tested at more realistic aircraft heights.