1) The thing is YOU DIDN'T MAKE 3.5 ROI! That's what we're talking about you silly goose. You aren't earning $7.5 a day per 1070. Like you just will numbers out of your ass and go 'nuh uh'. The whole reason I brought it up is because we AREN'T making that sort of money and it's more profitable holding BTC then investing it in mining hardware.
2) Why did you magically make an extra 5k in five months?
3) Your numbers don't even make sense. Jesus...
4) LOL hardware doesn't increase in value, it depreciates. And no, the prices of GPUs have relatively returned to the original values so they aren't artificially worth more (nor would you sell them right now anyway).
5) When you would sell them, your quoted 'five years' down the line they'll be worth about $70 a piece.
I understand that it's hard to believe or simply understand but:
1) It's simple - I did. The recipy for today was simple SIGT(~1BTC), BTX (~2.5BTC), XSH(0.8BTC) and several others less profitable. 0.8BTC of XSH was mined by ~15*1070 for 2 days. ~0.3BTC(part of the total SIGT) was mined by 2*1080 by 1 night with the shittest sgminer that made less than 8Mh on 1060. 10K in GPUs made around 5.5BTC in total for 6months. Some were cashed out. Some remains in coins. If I wouldn't cash some BTC earlier - it would be ~60K at current price.
2) It's simple - price of coins change every day.
3) Yes - these numbers doesn't make sense for nichehash/zpool&yaap's/ethereum/zec/xmr and others mining and cashing out imediately. For most of those who mine only with x$/day in mind they don't make sense.
4) 1060/6 just before June pump cost <200Euro. You can check the price today. So even used they still cost +/- the same or even more - it's hard to find Samsung memory in 1060 nowadays.
5) Actually I don't care whether I would sell them or not in five years. I think in a year I can throw them in a trash and buy new generation of GPU's.