That's interesting - it's a very hi-fi kind of concept, but I don't think a truly uncolored sound is possible with the 1940s-50s guitar pickup technology guitar makers still use; a true uncolored one-to-one replication is hardly accomplished using the best $10K microphones. Being in the studio every day, you can record a vocal with a fabulous mic and still it doesn't sound exactly like the person singing in the room. There's always coloration.
How much more colored is a $200 pickup that works on technology invented in the late 1930s, when carbon button microphones that made everyone sound pretty nasty were the universal standard, even in film and on recordings (the early Neumanns excepted because they were still rare, and of course, they had coloration too)?
People think that all a pickup does is electronically sense the vibration in the strings, but all you have to do is plug in, turn on your amp, turn the guitar volume up, and knock on a knob or the top of your guitar with a knuckle, and you will hear how microphonic guitar pickups are. They will pick up the sound of your knuckles hitting the guitar, and that has very little, if not nothing, to do with sensing the string movement.
Thus the wood -- and how it vibrates, sustains, affects the movement of the strings and a million other things -- plays a more substantial role than people realize.
But the pickups themselves can't truly be hi-fi devices because you're not moving air in front of a polarized backplate, and you're not pushing air into a moving coil, ribbon, or other diaphragm as with microphones. A guitar pickup senses things magnetically (and via vibrations accidentally because the pickups are microphonic though they weren't initially designed to be). In any case, they are highly colored devices by nature.