As a violinist, this is exactly right. Violins are not standardized, and are certainly not interchangeable. Everything from the dimensions of the body and fingerboard to the exact locations of the "sweet spots" where the instrument will respond most fully will differ. It takes weeks or months to really learn to play a particular instrument, and a test that only gives players a minute will not reflect how well the instrument can sound in the hands of an experienced player.
Another issue is that the instrument will sound very different to the player than to an audience, due to the way the sound is projected out of the ƒ holes.
That said, I think there is a growing consensus that the Cremona violins are a bit overrated, and that modern makers are making wonderful instruments for a tiny fraction of the price. When I bought my current instrument I ended up with a modern American violin, which I preferred to old Italian and French instruments that cost many times as much.
Another issue is that the instrument will sound very different to the player than to an audience, due to the way the sound is projected out of the ƒ holes.
That said, I think there is a growing consensus that the Cremona violins are a bit overrated, and that modern makers are making wonderful instruments for a tiny fraction of the price. When I bought my current instrument I ended up with a modern American violin, which I preferred to old Italian and French instruments that cost many times as much.