Personnaly i think it still profitable if you have always the gpu and you doesn't need to buy them, cause the difficulty will increase in somedays i think so let's mine now, it is maybe the end of mining profitable !
I think it is still very profitable now.
If you didn't buy gpus over priced then it is still a profitable decision, holding coins is always a good decision and with 31mhs on a gtx 1070 (presumably you can get more), you'll be netting 1.77-1.9$ per day as of current rates, even if you're left with 1.5$ as profit that's an ROI of 200-250 days depending on difficulty if it doesn't bomb as much more. That's a pretty good profit for a passive income business, if you hold coins and they go up, more profit.
The problem is that the difficulty will go up more and more with the passing of time (very nearby time). The problem is here in Italy I see people building 25.000-50.000 Euro worth of rigs with RX series(yes I have setup some for them as they have bought blindly) and they will surely increase difficulty.
One of my personal rigs which consists only of 3 Nvidia cards I have switched it to Zcash mining with EBWF Zcash miner. I was running them in Nicehash for Ethereum mining but I don't think it's worth anymore. Zcash mining gives me 7-10 USD more for a card if the coinwarz calculator is right.
The increase in diff is mainly because of the ice age, not increased hashrate!
