Been interesting to follow this discourse.

A few months back I encountered a good test scene for "reds" by chance. ( Mostly because I was there and like Volkswagens )
As was my habit, the camera was set to auto white balance, which normally with the Fuji does a good job. In this instance it rendered everything too cold but white point picking in the raw file fixed that.
With the overall scene and light levels I did a quick think and applied -1.3 exposure compensation. Once the file hit the computer it needed a further -.3 to tame some highlights.
What made it an interesting exercise to me is that there are at least 4 different "reds" in the scene along with varying greens and blues, most of which are "man made" colours.
The first image is a 1/2 processed file, just WB and exposure adjustment. The 2nd image is an attempt to bring back detail in the shaded areas and to present the colours as close to what I saw as possible. It is mostly correct, the glaring deficiency is in the greens of the vegetation in the background which suffered during the shadow retrieval.

The same way as nature presents differing "reds" we get a variety of manufactured hues and surfaces and I feel in this day and age the "red" issue comes down to a combination of the cameras exposure parameters when dealing with colours, the raw conversion tool used and then refinement ability of the chosen software.

It would be wonderful to be able to replicate the above images using a variety of makes and models of camera gear and then to explore the differing editing programs available.

I reckon we would end up with some distinctly different renditions of the scene.