Do you know what makes a "master" violin?
The stories one tells about it.
In terms of substantial difference between the sounds of the ancient violin made from wood cut in a fairy glade by the full moon, and the sounds of violins mass-produced on precision CNC routers and made from ordinary, stable, kiln-dried quarter-sawn spruce and maple (and sold for $100)... there really aren't any differences. Well, not until one discovers the stories behind each instrument. Since the experience of music is such a subjective one, it welcomes input from the most surprising sources. Music is a psychological experience and, lacking narratives, we often find little to distinguish similar sounds from each other.
I remember being shocked by Edward Herron-Allen's book, wherein an anecdote is related about how a certain audience, separated from the violinist by a sheet, could not distinguish between the genuine Strad and some other vagary. I mean, this other "violin" wasn't even a proper violin, as the story goes. Yet, without context, the two instruments blended into sameness. There was little of measurable qualitative difference between them, even if one of them was once submerged in volcanic ash and the other was not.
Making the violin, by hand, in the form that emerged in the mid sixteenth century from Brescia or Cremona, is a very difficult task. It takes a good deal of care and experience to get that form just right. There are plenty of bad ones made, but the actual bar that separates the bad from the good--in substantial, audible terms--is set much lower than you might expect.
The reason why people will still buy a $30,000 violin from a modern master maker (or very much more than that for a famous, old one) is because they have a gap in their minds that needs to be filled with the right story before they can properly channel their own creativity. To people who believe in the wonders of ice-age wood or the pedigree of a good, old fiddle, such an instrument will infuse its magic into them and enable them to create. It becomes a muse of sorts.
A hand-crafted instrument--especially an old one--is not just an instrument, it also acts as a talisman.
That's my opinion, anyway.
(Disclaimer: I am a violin maker)