How would you define "accuracy" or "faithful transparency" in a measurable way? You mention "science," and science requires observability or measurability.
It's been done. And the theoretical FR curve measured at the ears that represents the FR of GSIAGR doesn't translate into the headphones that are accurate or preferred. Part of the reason is that a simple FR curve (and btw, you haven't even defined where you're taking the measurement from, i.e. in the canal, at the external auditory meatus, etc.) does not fully describe for what is heard. In reality, sound waves are striking the pinna at all sorts of different angles of attack, each with various millisecond delays and differences in amplitude with respect to one another. How, pray tell, could you possibly represent all of that with a single amplitude vs. frequency curve?
Again, you need to define how one should measure "accuracy." If you can't observe or measure it, it ain't science.