It has always interested me that we treasure the old Cremonese instruments for their age, but their great value began when they were new. I’ve read a few great players admit a preference for modern instruments over their very old performance instruments — face it, we tend to get excited, knowing that a performer is going to be playing a Strad or a Guarneri del Gesu. No one promotes that an artist will appear in concert with his modern instrument.
I used to participate in and haunt discussions on another forum with several makers and dealers, and the makers even admitted something intangible in the sound of the very old instruments versus their own creations. But as far as the wood holding up, as long as there is attention to humidity levels and temperatures stay out of extremes, I would think that the wood would hold up for at least several more lifetimes. And probably better in use than in storage.
I know that those makers I mentioned earlier looked for well-aged wood, as any furniture maker would, too, unless using kiln-dried stock. Otherwise, the curing process might yield a warped instrument. And I understand that any real pernambuco wood for bows is very old stock anyway, for stability, but that it can no longer be exported from the rainforest sources.
Anyway, I’ve often wondered myself at what point the great old instruments ceased just being old instruments and became highly treasured masterpieces. Were they so appreciated when new? Or did they become something more as they aged? And who influenced their level of appreciation? Was there a champion for these makers who brought them to prominence? Johann Sebastian Bach was nobody until Mendelssohn discovered and promoted him more than a century-and-a-half later. Then he became the standard for generations of composers and music theorists.
Sorry, I ramble on and on.