the problem? some coins are just way overvalued now. they have small teams, no earnings, often no real use or product, yet they are worth billions in market cap. many of the big players in crypto will go bankrupt if people keep pushing them......
The most of cryptocurrencies (95%) are just bubble. But nobody know when this bubble will burst.
I think that your prediction about Ethereum will not come true. Here is the reason: Ethereum is most usable blockchain with its own working smart contract system.