I have all kinds of problems with the quoted paragraph:
"wing design from the DC-9-33 made in Korea." ???? Not sure whether this is supposed to mean: a wing designed in Korea, or a wing manufactured in Korea, or a DC-9-33 made in Korea, or all of the above, or none of the above - poorly structured sentence.
The B712 wing was the DC/MD design that served for 50 years - outsourced to a Korean factory (Halla) by Boeing for that particular version. Unless one has an outdated view of Korean manufacturing skills, it's no different than the previous made-in-USA wings. It was (always) a
simpler wing, appropriate for a less-expensive shorter-route jet (simple two-position slats (or none in the DC-9-10) and simple drop-hinged flaps)
I don't see any evidence that the B717-200 is a "crippled" design. Delta laps them up and jest luvs 'em. Certainly not aerodynamically (it may have been crippled during production life due to market positioning and changes, post-9/11 aviation slump, more modern competitive airframes overall, etc. etc. - but not the wing)
Not sure how much advantage a "big" wind-tunnel offers over some other size (MD did have their own wind tunnels, and access to others (NASA/Ames among others).
https://rotorcraft.arc.nasa.gov/Publ...cklin_1994.pdf
As with any logical chain -
first one has to prove the assumptions are true, accurate and applicable - only
then we can discuss whether the conclusions are true.
In other words, the "history" given above seems questionable - but your title is often very true - many aircraft have most certainly depended on unique wing engineering for their existence.