Don't forget that the difficulty [1] will increase over time. By using the calculator [2] with only a 5% increase, zero electricity costs etc. we don't see any return at all.
The difficulty will increase, but the price may increase.
I remember a year or two ago I was calculating all my BTC mining efforts on its value being under $30. Some efforts were break-even at sub-$30 exchange rates, but now in retrospect were well worth it.
In addition, that second link helps us work out what equivalent hardware at home we could use to accomplish a similar (non)return. Purchasing an AMD HD7970 graphics card, with a hash rate of 0.7MH/s, and mining with that could arguably be cheaper in the long run
The problem comes when you start factoring electricity and so on. In my calculation the difference is just too little. Plus you have the advantage of not investing time into it.
That's true. It would start being worthwhile at around 70$ (maximum price was iirc ~48$ recently). It may be very well possible to get an return especially if you believe in litecoin (328 times increase in 2013 [1])
I remember a year or two ago I was calculating all my BTC mining efforts on its value being under $30. Some efforts were break-even at sub-$30 exchange rates, but now in retrospect were well worth it.
But the big term is may, as it also may decrease.