what is a difference?
First as a caveat: I am a violinist, I have been playing a (wonderful) Pietro Guarneri, made 1702 in Mantova - of all places, as he moved away from influence of his father Andrea, his teacher (Niccolo Amati) and the up and coming Stradivari.
The most important sentence in this remarkable test is: "Modern makers should be very happy"
Indeed modern makers are nowaday truly much better than ever before, and there is a real sense of excitement in the community, that we are actually overcoming the difficulty of finding an aedequate instrument be it not a Strad or a similar instrument be those four or five, almost uniquely italian names.
There is however a difference between blind tests: In all my testings of modern instruments i have often found a modern instrument which tries to and sometimes succeeds to emulate the sound of a Stradivari, or sometimes even a del Gesù - but rarerly if ever have I found a modern instrument trying to sound like a Stainer or like an Amati, or even like a Pietro Guarneri Mantova, which is actually a blend of those two stiles. In my opinion an instrument reveals its differences whilst working with it, over months and years, not in a testing.
This might seem like a bland excuse, but I really like my fiddle, because it is not better, but different, and I get outstanding results from it, even though I very well know, that I could grab a modern fiddle costing a % of it, and probably in a few weeks/months/years I might get similar results.
Please don't ask why I don't do it; i might, is all I can say.
But there is also a useful meaning: We have all noticed that prices have not doubled, not tripled but gone ten times over prices just a couple of years ago..
As always, the bigger financial investment is no guarantee for better return, as you have to work with it to make it sound..
And as a slightly nasty addendum: Curtin is a well respected violin maker who's made his name for perfect copies of old instruments - just so you know, what is a desired outcome. But again: modern makers can and must be proud!!
As to bows, that is a whole different chapter again!!