The price of the ERC20 token does not depend on the price of Ethereum, if the price of Ethereum rises it does not mean the price of the ERC20 Token will rise too, and vice versa. Because the actual price of the ERC20 token is influenced by the Ethereum price, but influenced by the project itself, if the ERC20 token has a caring team and a large community then the price can increase positively in the market.
And if we find a good ERC20 token, we can really get rich.