SHUT UP AND JUST ACCEPT MY TRUTH - hehe, just kidding!
accepted... well it's accepted that the actual pickup wire can be vibrated in really high volume situations... true... but this is not that. he's doing this at really low volume and amplifying the heck out of it. also, showing it on a strobe. literally shows tapping on the wood is being picked up by a magnetic pickup.
controlled/predicted... i was trying to acknowledge that very point in the sentence regarding "at the end of the day... yada yada... too many variables... yada... impossible to predict...yada... so you just have to go with your intuition and develop your own recipe". iow, building out of mahog and maple is a lot more established than concrete so it is predictable in the sense that the outcome is much more likely to sound good with the std pickups/strings/amps/etc available.
I think he set out to prove that it does MATTER in a way that is less subjective -and on that mark he hit the spot. as so many have eluded... most of these types of 'proof' videos can be easily refuted by so many variables... ie "that difference can be explained by how hard you hit the string here vs there" etc... and he really did a good job eliminating variables. it is the only video of this type that I think I have ever seen where someone actually proved something. what did he prove? that the magnetic field of a pickup is in fact influenced by the vibration of the wood and subsequently the pickup itself.