I was looking at ETH and as far as I understand, this coin is mainly successful because of the ICO's nowadays.
ICO's are booming and it looks like it never ends. But what if all ideas are gone and the amount of new coins which use/ need ETH are decreasing. Would this have much effect on the price?
Maybe someone can correct me if I am wrong?
That's correct speculation about ETH and ICO relation but one thing is sure that ICO will never go down. As many countries are now accepting it in legal way its getting even better for ICO and they are KYC verified. This means people will never stop investing as there money is more secured as compared to previous ways of investing.
If in any worst case, all the ICO are gone then ETH still rule the world because other alts will be traded against it for its higher prices and keeping the balance of market cap the same as it is now. But that's just what I think, and things could be worst. ETH ~ 0