One obvious reason that most people think of is that gold and silver prices have been in decline since 2012, down to about 1/3 of their value at that time. But there is another reason that is obvious but not talked about too much. That reason is the internet.

The coin market is not much different from the other retail marketplaces. Sales are moving from brick & mortar stores to e-stores. If there is any doubt about this phenomenon a visit to ebay, amazon, and other retail venues will reveal the magnitude of the on-line coin market.

With this enormous retail outlet for coins comes the obvious effect of increased supply. Where formerly a search for a 1909-S VDB Lincoln Cent would take place in the buyer's local area with visits to a few coin stores within reasonable driving distance. So there might have been two or three coins available. I just now performed a search on ebay for this coin and there are 556 listings mentioning this date.

This increased supply has the effect of softening prices on coins, demand assumed equal.

Thoughts?