In nature silver is 15 times more common than gold, yet the gold/silver price ration is ~ 90 to 1.
Silver is also heavily used in electronics, so if the price went way up that would be inflationary.
Historically the price of silver remains flat for decades and then suddenly jumps.
So it would seems silver has a lot of upside but it also seems that the powerful interests have an incentive in keeping the price suppressed.
The famed gold to Silver ratio is often used to evaluate Market prospects, or current conditions. During the time that silver was present in ordinary circulating money, which may be a thousand years, that ratio held true in terms of its value. It does not always hold true in terms of Market pricing. For example, platinum is 10 times as rare as gold, and traded for many many years at least double the price of gold. But it actually fell below the price of gold in recent years as Palladium replaced Platinum in most cat converters. and is very slowly recovering at present. While the gold and silver ratio makes logical sense, I think its value as a predictive tool is nil, because the overall picture was irrevocably skewed by the near Universal practice of valuing it in currency at about 15 to 1.