Preference for the sound of certain instruments is a subjective thing, and can be influenced by the piece itself, the style of playing, and the cultural conditioning of the audience. I will illustrate this by comparing it to the whole "period vs. modern style", or "historically informed performances (HIP) vs. individual interpretation" debate in classical music.
When HIP/period performances started gaining popularity in the 60's, many musicians outright rejected it. The argument goes, "if Beethoven had access to a modern orchestra, he would be using a modern orchestra", vs. "the music was composed for smaller orchestras and less sonorous instruments of the period, so we should hear music in the same way". In 2023, the argument is still not fully settled. For some composers like Bach, HIP has more or less won the day. However, most people still perform his keyboard works on modern piano, which is a far cry from the harpsichords used by Bach. For others (like Beethoven), there have been attempts at playing his work with period instruments and smaller orchestras, but nearly all recordings use modern instruments and modern orchestras.
Classical instruments like the Strad are the same. In comparison to modern instruments, Strads are thin sounding and lack sonority. Their fame comes from their beautiful balance and singing tone. Modern violins are more sonorous and sound much richer. Now, whether you prefer Bach being played on a thin sounding Strad or a rich sounding modern violin is a matter of taste, just like you might prefer a piano for Bach over a harpsichord. I have a recording of a Beethoven piano sonata played on a replica Erard that was used by Beethoven. First impression is that it sounds like a toy, and I did not like it at all. Then I wondered whether it was the fault of the pianist (Ursula Dutschler) who was using modern tempi and not the tempi indicated by Beethoven (which these days, most musicians think is too fast).
I have also found that my own musical preference for the style of performance has changed over my 40 years of listening to classical music. When I was younger, I preferred Bach chorale works conducted by Richter or Klemperer for their huge scale and sheer richness of sound. These days I prefer the smaller scale historically informed performances, especially by Rudolf Lutz and Leohardt/Harnoncourt.
Comparing a Strad to a modern violin is the same as comparing any historic instrument to its modern equivalent. Violins have not evolved as much as pianos, so the difference is not as obvious. But an Erard or Graf piano from the 1800's sounds obviously different to a modern Steinway or Yamaha, and you will probably dislike the older pianos. This does not mean they are inferior instruments, they are just different instruments, and they need to be played differently.
So: that blind test comparing a Strad to a modern violin, with the modern violin winning, means little to me. Did the audience consist of people they picked off the street? Or were they professional musicians and musicologists? Just because there is a McDonald's nearly everywhere does not mean that they make better burgers, does it?
Do I prefer the sound of a modern violin over a Strad? Of course I do. But then, I have been conditioned through a lifetime of listening to modern instruments to prefer that kind of sound. But, would I prefer the Strad if I heard it with a different violinist, playing a piece with a period correct style? I don't know. I can give many examples where I prefer the older instruments, just like I can give as many examples where I prefer modern instruments, but this would be really boring for any non-classical music enthusiasts.
