I calculate the main prices of ETH and also BTC price regarding the mining process and costs. miners are the main people that affect the price of BTC and ETH. if the prices of coins will below the mining costs, the mining will not affordable. in general, if we consider the average prices of mining in all of the world, we conclude that the lowest prices of BTC is about 6000 to 7000$. and this amount for ETH is about 400$. so if ETH decreases more than 400$, the mining of ETH will not affordable and miners will migrate to other alts. so this migration will cause stopping the mining of BTC and ETH and also will cause the price of the transaction. in long-term, this causes the raising of the price for ETH and BTC.
I think ethereum is currently very cheap. and this is a great opportunity to continue to buy. why I say this because ethereum itself will continue to grow and its demand may exceed the bitcoin and it is also possible eth dominate the market in comparison to bitcoin. and also ethereum being a pioneer token coin that greatly helps the development of a business and project, many successful projects are still running using token from ethereum itself.