I was "talking" with a friend on Facebook about this last night. He felt that the test showed that a Strad's simply not worth millions when a violin that's "only" $150k sounds as good or better. This is what I responded with:
"I only half agree. I know that whenever I pick up a different guitar, it always feels great - as long as it is a basically playable instrument. Play it for a few days, and the impression may well change. Granted, I'm not a concert violinist, but I think that the very personal and subjective opinions one forms about musical instruments (or stereo speakers, or art, or flavors, etc...) take some time to crystalize. First impressions often miss the nuances and are overwhelmed by the bigger differences that may seem great at first but which may not hold up over time."
Also, much -- most -- of the value of a Stradivarius is because of its scarcity and irreplaceable nature. It may still be the standard against which all others are judged, but it's not inconceivable that modern builders could make a better sounding instrument, even if the conventional wisdom still holds that a Strad is best.
This occurred to me recently when I bought a 15 year old Strat (not Strad) to gig with instead of my '59/'61 vintage Strat that I've owned since 1974. OK, a Fender's not a fine violin, but still... the $650 bone stock '95 American Standard Strat is a superior instrument to my beloved $15,000+ vintage Strat. The new guitar plays better and sounds better. And why shouldn't it? Fender had 35 years to figure out how to improve the guitars and make them more consistent. High-end violin makers have had hundreds of years to improve their craft.
I don't think blind tests are particularly useful at evaluating preferences amongst highly subjective things.