This statement I don't understand. The difficulty on Bitcoin is rising even faster and more predictable than Litecoin. With this calculator: https://tradeblock.com/mining/ if you select an Antminer S1, $500 as the price, $0 for shipping and misc, even 0% pool fee, $0.05/kwh electric (VERY conservative), you never see ROI. The first month you make $191, then $123, then $78, until the power costs more than it's returning in BTC.
If you had bought the Antminers in November, December, or January, you definitely would ROI.
I bought in February, so should be on pace for mid May ROI in BTC. ROI in fiat sooner if the BTC price raises.