An odd comparison, and hard to quantify. Are the same people who look to invest in cryptos looking to invest in silver? I wouldn't have thought so - pretty different commodities!
Absolutely different commodities indeed! This to me is like two different separate spaces entirely and I do not see how much they correlate. I do not expect that in the long run, Silver nor gold will become obsolete and then attention will totally shift from there to digital age.
These commodities have been used for different things in the past, they are valuable and that will not change. Cryptocurrencies as well will have its own market and in anyway, as things evolve, we might see it being a preferred choice, but that would not eliminate the other commodities.