https://bitcointalksearch.org/topic/m.12913379
Every mining company let you believe the price is right so you can get ROI, but factors that are hard to understand for the most people (difficulty) and a factor that can't be predicted (BTC price), makes it unprofitable in the long run.
Well said, there are to many factors you can't predict
I think people just don't know what they are talking about. For example that post. Sure the S7, at least at 230$BTC price was ridiculously overpriced, and now its a bit disappointing that the last batch has less hashrate but the same price, but think about it;
If a current gen overpriced unit can ROI in 4 months. How fast you think you would ROI if you purchase the right hardware for you? A S5 can have twice the GH/$, in the post's case, this would be time to ROI in half, which seem pretty safe.
The S7's first batch were indeed icky because many people would not ROI before the halving, but not, it is not the case. As such mining is amazing now, at least for people that got hardware before it became so expensive