Interesting thought regarding the comparison with vintage cars. I always assumed that some crazy rich guy that is a collector would buy one of these rare pieces. And as he is a collector he most certainly puts the grail in a box and calls it a boxqueen. Maby he wears it at very special occations but thats about it. And thats why its quiet until he dies and the rare pieces are obtained by some random dude that happen to be a relative to the rich guy and has no interest in watches but loves cash so it ends up on auction again.