Do you think another scenario could be a loss of interest in Ethereum when there is the shift away from mining to Proof of Stake?
People being able to mine ether themselves and then trade it for other cryptos or fiat I believe contributes to the popularity as well just like it does with other coins.
It may not be a huge price contribution once casper arrives but it could hinder peoples interest especially if they are arriving late to the party.

One positive contributing factor could be the ICO's getting to a point where more of them start completing their projects and proving the system works.

Thanks for the thoughts @pynetx