It seems to me not correct that the price of most ERC20 tokens depends on the price of the ether! What do you think?
Never, erc20 token price not depend ethereum. Every alt coin price depend community and trading volume. Erc20 token just created using ethereum blockchain, it doesn't mean ethereum controlling price of all erc20 token. No value of ERC20 it self if there isn't trader community to trade the token. Any one able to create erc20 token by using small gas fee. But it will be worst if no community for trading with it.
Yeah sure, I agree with your point, erc20 tokens price does not depend on eth price, that they are hosted on the ethereum network doesn't mean that it depends on eth price, the price of tokens depends on the market demand and supply.