The cards would pay for themselves in less than 4 months

You people are also forgetting about the impending ice age, and the difficulty bombs.  As more and more people increase their card counts, your "profits" decrease drastically.  You can not rely on your calculators anymore as they do not incorporate these items.  Even the calculators state that "The calculations are based on the assumption that all conditions (difficulty and prices) remain as they are below." Also, ETH has been on a free fall due to the bloodbath that is crypto right now.  
 
To lift right from a reddit thread.  https://www.reddit.com/r/...e_roi_is_gonna_getcha/
5 Rx580 145MHs rig:
6/4/2017 - 2.92 Eth Per Month
6/29/2017 - 1.77 Eth Per Month
Loss of 40% Eth Rewards in 26 Days
Assuming the same decline rate (which is probably underestimated) That would mean 1 Eth per month in another 26 Days (July 22nd).
I'm guessing around .5 Eth by August 15th or 20th.
 
You people are making assumptions on the fact that the difficulty will stay the same, which it WON'T!  It will only increase, in orders of magnitude.  And with ETH currently worth under $300 that means this rig by August will probably be making less than $150 dollars a month unless ETH picks up.  Which means by September, he'd be mining .2 ETH or less.  And remember..China is making massive farms for this too.  
 
In short, don't build a rig expecting it to pay for itself in this current market, if you can't afford it don't.  Only play with this money if you can truly afford to lose it, and if you can truly afford to pay for the electricity that you are going to use to run it.  I'm not try to scare you away, I am trying to make you understand that this is not a get rich quick scheme and that this is not easy money.  If you wanted that, you needed to start 4 months ago.
 
I would honestly say if you're going to spend the money to build a mining rig, instead use that money to buy into ETH on a dip instead.

People forget that every time 1060 and 1070 cards come in stock, they sell out instantly even at their new inflated costs, and with mining cards coming into play, this fantasy that "I can easily make a grand a month if I spend 5 grand right now then I can make it back"  is just that right now, a fantasy.  Most of the mining subs are rife right now with newbs complaining about how last week they were making more than twice what they are now, and they all think they are being ripped off and don't understand that as more people start mining, it becomes more difficult to become profitable.  As people I remember in May I could easily make almost 30 dollars a day with my 2 1080's, then in June it dropped to 20 dollars, then 15 and now it's under 8 dollars a day.  
 
To put that into perspective, what I was making in May on 2 1080's with other coins, is more than what you currently make per day on 8 1070's.  8 1070's right now, right this moment will get you 0.0967 ETH per day, with a revenue of $25.93 per day, with it rapidly dropping.  So it will cost you $4500 for the cards due to inflated prices, then you need the risers and the boards and chips, power supplies, so in total you're going to need about 6 grand give or take (low balling on cards at 500 dollars a piece which is doubtful at best haha probably more like 550 600). IF everything stayed constant, you would need 240 days to pay for everything, and that is not including power costs.
 
The current difficulty is 988,092,355,654,644.000.  Yesterday it was 978,645,128,107,786.000, 3 days ago it was 964,152,686,787,839.000, and a week ago it was 936,584,239,063,846.000, and a month ago it was a mere 
534,854,242,322,587.  So yes in 3 days the difficulty went up by 10 trillion, and it doubled in a month when it was already at a staggering half a quadrillion.  Oh and the current hash rate is 57.31 Th/s.  Think about how many cards that is.  June 1st it was only 34.17 Th/s
 
 
 

It's always been a balancing act for digital currency. The value needs to keep going up for miners to make money given the massive pools out there. Etherium isn't going up in value fast enough to keep up with the buying spree. This just means they'll flock to another currency or sell their cards.

Ranmacanada
People forget that every time 1060 and 1070 cards come in stock, they sell out instantly even at their new inflated costs, and with mining cards coming into play, this fantasy that "I can easily make a grand a month if I spend 5 grand right now then I can make it back"  is just that right now, a fantasy.  Most of the mining subs are rife right now with newbs complaining about how last week they were making more than twice what they are now, and they all think they are being ripped off and don't understand that as more people start mining, it becomes more difficult to become profitable.  As people I remember in May I could easily make almost 30 dollars a day with my 2 1080's, then in June it dropped to 20 dollars, then 15 and now it's under 8 dollars a day.  
 

 But if you go back to March you were lucky if you were making $5/day with both cards.
 The only reason profitability got so high was a massive across-the-board though not all at the same EXACT time jump of almost all Altcoins in a 2 month (mostly) period.
 Bitcoin, on the other hand, had been ramping up for quite a while at that point - but even it took a BIG jump over the last 3 months.
 
 Looking back on this period from 5 years down the road, I anticipate it will be known as "the silver age of mining" as opposed to the late 2013/early 2014 Litecoin craze being known as "the golden age" - but if the current period lasts 3 more months or longer THIS will be the golden age and the earlier time the silver age.
 
 

Best thing to do is, sell your old cards in the inflated market, use the extra money and opportunity to upgrade to a 1080ti,

Seems like the new "mining-specific" cards are starting to ease the strain - a little.
 
 GTX 1070 availability has improved a LOT this week, and pricing is dropping back down quite a bit towards "2 months ago" prices.
 
 Might also be that fewer folks are jumping in, given the massive DROP in profitability on almost everything altcoin the last 2-3 weeks, as pricing slid quite a bit across the board while "new hashrate" has kept growing.
 
 

It's putting a lot of money in the pockets of the 3'd party card makers and AMD and probably some into NVidia's pockets - short-term.
 
 The issue is when the crash comes, there's going to be a GLUT of used cards on the market killing sales of new cards for a few months and probably hammering new cards sales for most or all of a year.
 
 THAT seems to be the primary driver behind AMD and NVidia and many/most of the major 3'd party card builders pushing the "mining-specific cards" - it's an attempt to reduce that glut by making cards with very low usage factor outside of mining.