The ICO cycle is dependent on both human psychology and the availability of VCs, which are in limited supply. Ultimately the ICO system fails when not enough investors are putting their money in, and this is typically produced by an external factor that affects the overall market.

At the moment the major factor that will affect the Ethereum price will be the instability in the Bitcoin ecosystem over the next few months, due to the BIP148 vs Segwit2X situation. It largely depends on how many mining groups show themselves to be untrustworthy, and that is a simple matter of watching. The prudent investor will simply hold during this turbulent time.