Interesting post...
I grabbed the country store version of Gilly's building...it was sitting on the layout awaiting final placement...and put a scale ruler to it. 'Standard' doors are 6'-8" in height. The rear door of that structure scales to a perfect 6'-8".
I have never questioned the 'scale-ness' of RK buildings...until this thread. Now I've put that to bed again.
But, overall I find that in this hobby, this O3R 'scale' is really a mish-mash of 'scale-ness' anyway. People, cars, trucks, buildings, engines, railroad cars, passenger cars...and especially scenery (think:TREES) are typically way out of whack for true 1:48, 1:43,...whatever you consider 'O-Scale' to be in your corner of the world.
Here, go for a short drive or walk...or just look out of the window. Wouldn't you say that most trees in general TOWER over their surroundings...houses, cars, trains, etc.??
Yet, most of us populate the layout with trees as if the whole world were an arbor nursery. I do it, too.
Except one time, when I built the HO display layout for the store (LHS). I focused on ensuring that there were LOTS of trees, and they were most typically of a common scale height. Guess what?....That's the first comment about the layout when people see it...the trees. So the undersize/oversize this and that elsewhere just doesn't matter.
The whole thing is a compromise when it comes to scale and fidelity. Techniques like 'force perspective' help to soften the differences. It's what we have to work with,...and how we chose to accept it.
But, that's just one man's humble opinion...
KD