As for the case of bitcoin, I might say that the supply isn't really dictating the price nowadays but the demand from people all over the world. The supply is ever increasing every time a block is found, but the demand on the other hand is pretty hard on the buying side, causing some kind of price bumps. There are only 21 million bitcoins to be mined until 2140, 16.9 million are currently in circulation, 1 million of those are possibly lost in the void, and less than 10 million are in circulation. It's been like this for over 3 years now, but looking back, the price is not that extravagant compared to what it is today simply because demand is simply not there.