ETH price are sinking like Titanic, I think the mining is dying, and only will be profitable again when the many farms and miners will get out of the game and the diff will be back to ~2015-2016 levels.
Mining of the ETH began in the 3rd quarter of 2015. In 2016, the profit reached up to 5 dollars from one video card (RX 390) per day.
It was a very good time. The decline in mining was in 2014 and early 2015. At the beginning of 2016, when I started mining, the hashrate was near 0.6 TX.
1 video card gave about 3 coins per day.