I don't think mining was ever that profitable once it reached industrial scale (it was always a bet on the future, in which case having actual bitcoins is significantly more fungible).
There is a reason cex.io / ghash.io (the biggest mining pool) contracted out their hash power to other suckers (err I mean buyers) instead of mining themselves.
I used to know a fairly small miner, ~$2,000 a month turnover, who managed to rig his ASIC up to his heat pump in such a way that is heated his house and cooled the card. He lived in a fairly big house and it was always toasty even in the middle of winter.
It might still make sense for some people even when the margins are small
Oh I'm sure it might make sense even for a big operation, if there are special conditions or clever tricks that allow for cheap electricity and/or tax breaks. All I was saying is that in and of-itself mining was not a profitable strategy once it became large-scale.
There is a reason cex.io / ghash.io (the biggest mining pool) contracted out their hash power to other suckers (err I mean buyers) instead of mining themselves.