They can not be on all the time, why would you have them on when the temperature is above 76F? Waterheater can not be on all the time neither, they run in cycles, otherwise you are just wasting water/energy.
The problem is when you can't have them on 100% of the time, you could never recoup your hardware cost, because like you said, new ASIC will be come cheaper and more efficient, therefore driving up the difficulty, and your old hardware, when not on 100% of the time, will never recoup the cost. Which makes your investment a loss when competing against a real mining farm.
The problem is when you can't have them on 100% of the time, you could never recoup your hardware cost, because like you said, new ASIC will be come cheaper and more efficient, therefore driving up the difficulty, and your old hardware, when not on 100% of the time, will never recoup the cost. Which makes your investment a loss when competing against a real mining farm.
In the equation above the ASIC's hot water heater are on 20% of the time, silly. The transaction rewards and block rewards merely subsidize the electricity or amortize the unit cost. They don't need to pay 100% of the unit costs or electrical costs as that is just a bonus. People need hot water regardless, and some
people like hot water when its overcast in the morning or at night.They don't need to pay 100% of the unit cost, but they do need to pay 100% of the ASIC component cost, otherwise you are just buying a more expensive heater for no reason. The problem is, with 20% up time, there is no hope of ever paying back the 100% ASIC cost, even with the electricity cost savings. Therefore, you are indeed just buying a more expensive heater(that requires constant on internet) for no reason.