ETH was extremely profitable to mine (in terms of ETH not USD or actual profit) back in late 2015. It had a good launch and then I think those that bought the ICO ended up dumping everything and at the end of the year I think ETH traded at less than $1.

An R9 280X didn't have any DAG issues with a low epoch, it actually mined at 27-28MH/s however it ate 200 Watts of power. So with $0.10 power, you were mining at a loss but generated 1 ETH per day per 280X.

Imagine mining ETH with a single 280X back in late 2015, to sell at $1400 in Jan 2018? Basically what Satoshi felt pretty much. However most like me either didn't mine at a loss or they mined and sold when ETH hit $10 or $20.

To mine at $1 a coin and sell at $1000 is extremely rare.