From $150 to $0
Per the report, the profit per month of mining ethereum, one of the world's top cryptocurrencies, by means of a graphics processing unit (or "GPU") has fallen precipitously since the summer of 2017. At that time, an individual miner could reasonably expect to earn $150 per month and per rig when mining ethereum. As of November of 2018, though, that same miner will likely earn $0 for the same efforts.
There are multiple reasons why the profitability of mining ethereum has plunged. First, the price of ethereum itself has fallen considerably. Around the beginning of July, 2017, ETH tokens sold for close to $300. As of this writing, they are barely half of that and are trading at just over $156. For miners who rely on the sale of the tokens that they produce in order to generate a profit, a significantly lower token price means fewer opportunities to make money.
Beyond the price drop, there is also the broader issue of the cryptocurrency space itself. Cryptocurrencies have fallen out of favor relative to their peak in late 2017, with trading volumes and prices down across the board. Miners simply have fewer willing customers lining up to buy tokens, which also impedes profit-making capabilities.
Finally, the "hashrate," or speed at which a computer can solve the math problems necessary to be rewarded with tokens, has fallen. The higher the hashrate, typically, the better the situation is for miners; with a higher hashrate comes a greater likelihood of finding the next block in the blockchain as a result of the rig's problem-solving capabilities, and thus comes also a higher chance of receiving a token reward.
Not Just Miners
Individual miners are not the only ones feeling the impact of the shifts in the ethereum mining system. GPU manufacturers like Nvidia Corp. (NVDA), companies which saw tremendous interest in their products in recent months as the mining boom took off, have now seen revenues drop. Nvidia saw its revenue fall by about $100 million quarter over quarter. Susquehanna semiconductor analyst Christopher Rolland explained that his firm estimates "very little revenue from crypto-related GPU sales in the quarter, consistent with management's prior commentary that they were including no contribution from crypto in their [3Q18] outlook."
All is not yet lost for the digital currency space, though. Major asset manager Fidelity recently launched Fidelity Digital Assets in response to demand from institutional clients for better access to the space, for instance. It may simply be that individual miners and investors no longer find the quick profits in cryptocurrency which they may once have enjoyed and that the space may be shifting toward a new customer base.