In the beginning it was not so bad.. price would plummet but the coins ran out the dump sellers had. than the price would skyrocket back up! But than it has gotten to be more coins than buyers and sellers had kept plummeting the price. I won't be surprised if the coin becomes worthless because sellers are impatient to sell and will not wait and set there price lower than everyone else keeping the downward spiral.
ZCash should of kept a 1:1 with BTC. Buyers buy ZCash to do there anonymous transactions than cash out in BTC. Keeping amount near the same but instead just have a bunch of miners that want to sell so fast they they set there value one point lower.. price now becomes new price.. next seller does same.. price becomes new price.. repeat, repeat, repeat. Miners would have to work together and set the lowest value and not go any lower to get a standard limit set. But it will not happen as everyone wants to quick dump.. back in the spike period I would set a sell target price that was high and during the spike I would end up selling it.
The reason for the insane prices at start is hype, and ludicrously low supply. If there is only like 1 coin in the world, it will be worth a lot. Now there are thousands, or course price will be lower. People posting that everyone should hold are either retarded and don't understand supply and demand, and some other concepts, or are just wanting others to hold so they can sell.
Sure if EVERY SINGLE MINER, pool operator, and Chinese farm on the planet held, price might stay high longer, but if this was the case, it would be ludicrously profitable for any of thousands of miners to sell. Any investor could mine a few fractions of a coin on his laptop, and make a killing with no risk. It isn't smart to hoard all your coins when they lose a ton of value per day. Everyone is free to make their own choices. If someone mines 0.01 Zec, them holding will be drops in a bucket, so it likely won't affect price either way.
Reguarding the first few hours. It is completely and absurdly insane to believe the value would hold at $40,000 per coin, and so it is extremely risky to try to hold.
The reason for the price going down is almost entirely a factor of the increasing reward, and coins mined.