Revenue to maintenance is unimportant, price is. I purchased a bunch of S5 at 0.0028 which at 440 usd/btc means almost 2% per day from mining, so I don't plan to sell right now ;-)
If you can return your investment in two weeks +10 days, lucky you!
I think it would not be impossible to achieve return on investment... but returning it is not enough. You have to actually earn more than you invested in order for it to be worthwhile!