As already mentioned, one reason for the increase is the
cryptocurrency market, which caused a huge boom of graphics card sales.
However:
A: Some Crypto Currencies cannot be efficiently mined via graphics cards anymore and you need ASICs to do so.
B: The market has been crashing massively during the last weeks.
C: IF and WHEN the hype goes down, it might have an opposite effect. Because when that happens all of a sudden the normal vendors have a huge competition by second hand offers of crypto currency miner dropouts. So cards could even become cheaper than they "should be", causing the opposite effect we are at now.
It's speculated that there are also other factors.
Supposedly there is a
bottleneck of components which make them more expensive. This might be because they are already shifting to other components, especially considering memory. So this problem will go away again as well.
Furthermore we had a huge boom in PC Gaming in China thanks to
Player Unknown Battlegrounds. Supposedly 10 Million
link Chinese players. As this game is also quite hardware hungry this might also have increased the sales of graphics cards in china, especially when previously MOBAS dominated the internet cafees and only average hardware was required.
It's very likely that
Volta is going to be released this year. This could further reduce the price of hardware. Read this as "it will reduce the money/performance price" instead of "gtx 1070 getting cheaper", as old hardware usually phases out before it gets significantly cheaper. So combined with the previously mentioned decrease of mining boom and switch to ASICs this means that we will likely have a market of decently priced new hardware and tons of last generation hardware on the second hand-market.
So my suggestion is: Don't buy hardware now. If you are using 1080p now, stick to it. Maybe buy a last generation graphics card on second hand market (e.g. gtx 970) if you really need something as your old stuff broke.
If you have enough money though, you might consider going big instead.
Yes, the prices are insane now. But that's "only" for the usual spot of decent price/performance. However you can go, where the price/performance ratio isn't good enough for miners anymore, because these prices are still the same.
What I mean is this:
The GTX 1080 ti should cost 769€. It does cost around 1000€ though. (13,788 benchmark result)
You could however buy a GTX Titan XP instead. Which should cost 1138€ and does cost 1138€
link which results in a benchmark value of 14,884
So if you really have tons of money to spend, that would be another option to actually get a product without being "scammed".
Let's not get carried away here.