I will take the bait, but feel that you've included the answer in your explanation. though I may not be understanding the witness point explanation correctly.

But, surely there is some vibration induced in the surrounding material that the points are mounted in. Would it have a dampening effect or nullify vibrations? I believe it would to to some degree however miniscule and that degree would vary with different characteristics of different materials. However much more or less miniscule respectively.

I may not be understanding your point so I may be arguing the same side. For that I apologize.

Why does the wood/ the body have to be a black hole and completely absorb all vibrations? Is it possible to construct something so efficient out of wood? I would love to soundproof many rooms of my house with this technology.

What if the degree of absorption differed in relation to the characteristics of the material the witness points were seated. Because the strings are always connected to the wood at all times. There is no perfect machine. There is always loss drag friction etc. and different degrees/ more efficiently designed machines incorporate better materials to minimize that.

I may not be getting your explanation correctly regarding this either.

I believe that an outside source could impart enough vibration on the solid body of the guitar to cause the strings to vibrate and thus induce sound from the pickups. (I hope you were not just basically explaining that would isn't metal with this part. If so, I apologize for misunderstanding that too).

All of that being said; I do agree with the builder and creator of this fine "instructible" The material used isn't as important as the the quality of construction and pickups/ electronics used.

Also, I think that BIlly Gibbons and mid life crisis' points should not be disregarded so readily. Because there are truths contained in them that are valid IMHO.

Maybe I've not made sense to anybody but myself. But, I gave it a shot.