Ethereum is a serious fundamental asset, and I do not think that its price will drop by 90% of ATH.
Price of Ethereum might fall 90% from its all time high in a bull market. It is probabaly where price will bottom out from all time high. Question is where is the all time high for Ethereum in this bull run? If people think the orice above 4k is all time high for this bull run, they can wait for 80% or 90% discount and enter for a next long term investment.
If they don't believe it, why do they not enter now?
Honestly, Ethereum is a few cryptoccurrencies that I don't believe long term investment with them will cause loses.
Newer, younger altcoins will need 4 to 8 years to have a solid position in crypto market. BNB has gone through the first toughest testing period, others should finish it too.
Else, there is no strange to see altcoins with less than 4 years old have very highly volatile price.