In order for ICOs to generate market-cap, the ICO requires funds. In order for the idea behind the ICO to have the ability to take off, they wil require either Bitcoin, Ethereum, Ethereum Classic .etc ... Some ICOs can take various coins. So funds may be pumped into these coins so that they can be exchanged for ICO tokens. ICO token conversion is ultimately possible at the end of the ICO (given that the ICO was a success)
Maybe the more ICOs there are, the more we will see an increase in coins that are able to invest into the ICO.
Just Quick & Random Thoughts By Mr. EXPERIENCE