I am not saying any such thing. I'm not even saying anything much about what "scale speed" should be. I don't know the answer to that question; I could make guesses, but what would be the use of that? All I'm saying is that many people are assuming that it must be 1/4 of something or some combination of things for a quarter-scale model because that kind of model is 1/4 "the size" of the original, and that is wrong: it's 1/4 the length, 1/16 of the surface area, and 1/64 of the volume. There is no one number that measures "the size" of an object of more than one dimension.

I do think (but I'm not sure) that you may be right about one thing: whether a model in flight looks like a full-scale plane flying depends at least in part on how far away it is. That seems reasonable, but there may be other things that matter, too. When a model is just sitting on the runway and not moving, it seems clear enough that "scale speed" is zero: exactly the same as the speed of a full-scale plane sitting still. So if there really such a thing as "scale speed" for a model in flight, how does it go from zero to that particular fraction? Does it suddenly jump to 1/4 or 1/16 or whatever as soon as it starts moving, does it increase gradually, or what? I doubt that the answer is something we can simply calculate.