An ARF from a company like Hanger 9 in my opinion is constructed in such a manner that I think it would be difficult for the average modeler to tell the difference (I got one of there Cubs 4 years ago and let me tell you the craftsmenship was outstanding) What I am trying to say is that if you compare the end products they are so similar that it makes the models origin irrelevent.
I think you're mostly correct, but not completely. An ARF has to be covered, then put in a box to ship. In my experience, that means that even for .40 sized trainers, the wing halves are covered first in the factory, but the modeler has to assemble the two halves. That's not the case with any kit I've built, in which the halves are joined before the wing is covered.
I saw the wing fold in flight on a Tower Hobbies .40 Trainer ARF. There was absolutely no reason for this, since the plane was just flying along. I inspected the remains, and found that the owner seemed to have followed the instructions completely, but the designer evidently thought that a little piece of light ply epoxied into the wing halves would hold the wing together. In fact, the balsa center ribs had actually torn apart although the glue joint held.
Compare that with a kit, where the piece that joined the wings would be longer, and you would have better access to make sure the glue was in the right place. Plus, all the kits I've built recommended glassing the joint, something you cannot do easily (or at all) with an ARF.
The reason I'm telling this story is not to deny your statement that ARFs are well built, but only because I felt so sorry for the owner of the ARF I saw crash. He had paid $100 or so for a well-known plane from a well-known company. As far as I could see, he had built it exactly according to the instructions. And I saw with my own eyes, it just suddenly fell out of the sky. Fortunately, nobody was hurt, and the engine and receiver were fine.