Ethereum was extremely famous in 2017 which prompted an enormous increment in price from simple single digits to $1400 with lots of purchasing pressure from a retail crowd pushing the cryptocurrency high as can be. This was supported in those days in light of the fact that blockchain was being utilized for Initial Coin Offerings (ICOs) which implied that investors who needed to get new altcoins would put resources into Ethereum.
Source: TheCoinrepublic
I like to believe that, Ethereum can still reach the $1000 level even if the ICO are gone, the fact that it is fast and the fee is very small, they can shift their roadmap from ICO to being accepted in marketplace.
Ethereum has everything on it, the team just needs to be flexible, they have the support of the community, and new project that are not ICO will always find Ethereum has something all they need to set up their own token.