For the last six weeks, cryptocurrency has been all over the place like an infection... currency markets, GPU mining, global GPU shortages, and more. It's a volatile market as it's open 24/7 and doesn't close like regular FIAT-based trading markets. The latest trend is Ethereum mining (for the most part, anyway) and the global GPU shortage of the last 5-6 weeks.
Ethereum mining and its impending DAG increase (the difficulty in which Ethereum mining is set at) began a huge upwards trend a few days ago, its biggest rise in difficulty... ever. The downwards trend of the price of Ethereum didn't help, as it created the perfect storm for the temporary tank in Ethereum ROI from mining. For anyone who has just purchased, or is in the process of purchasing PC hardware (GPUs, PSUs, risers, etc.) is paying heavily inflated prices for something that was in the headlines a month ago as a great way to make money.
The difficulty increase and drop in the price of Ethereum has slapped us a few times across the face, in what feels like every day. I wrote an article that did amazingly well for us, as it was written at the peak of this as it began to really scale right up in difficulty, and down with price. Buying hardware at a huge inflated premium isn't good, with wholesalers, retailers, and everyone in between making a quick buck on the global GPU shortage.
If you had purchased 10 x Radeon RX 580s before the beginning of June for Ethereum mining, you'd be making some damn good money - somewhere in the vicinity of $2500+ per month before electricity (and paying off the hardware). This meant you could pay the cards off pretty damn quickly before the price of Ethereum began to fall, and the DAG increased by leaps and bounds. This was the issue... just as Ethereum mining became 'mainstream,' the fevered need for RX 400/500 series cards spilled into second-hand markets, into the GTX 1060, and even GTX 1070.
I'm not sure it's dead per-se; it has reached a stable point in it's cycle and trading values are normalizing. It will go up slightly as more ETH implementations/payment solutions are adapted and the demand increases. As with any coin, usually early adapters stand to win big: shortly after the split of ETC and ETH mining still brought in daily fortunes - those who held on before it reached $1 instead of instantly trading it off should have amassed some potential wealth by now. Anyone who just got in (mining ETH) during 2017 merely made pocket change if anything.
Every crypto currency goes through these cycles; a coin either gets wide acceptance (Winklevoss brothers/Coinbase - LTC and ETH) due to the underlying technology and overall utility, or it goes bust and becomes totally useless (for example Bytecoin - not Bitcoin - developers premined 80% before releasing it to the public).
The GPU shortage isn't over yet either, as many other coins can still be mined. The prospect of having thousands (of units) of coins worthless today picking up trading value over time still makes this attractive to many. Just like Bitcoin (remember the 10,000BTC Pizza purchases from 2013?)
Which coins are going to be big? Keep an eye on trading platforms (BTC-e, Polyniex etc) and read up on the technology behind each coin.