I think the course of the ethereum does not change because he is not a public person and it can be noted that the fundamental news doesn’t particularly affect the market due to the fact that the market is manipulated because it is only gaining popularity.
Yes. Ethereum is gaining popularity each day, although usage on the network has decreased (compared to last year's figures). I believe that the next step for Ethereum to gain traction, is to adopt Casper PoS and Sharding for greater scalability. If at some point in the future Vitalik dies, then the project should continue its own course. The vast number of developers working on it, and users supporting it, is enough for Ethereum to survive for many years.
However, as I've said before, people will react negatively towards Ethereum once Vitalik is dead. Prices will struggle to rise within a short time period. Just as FUD is happening with Bitcoin nowadays, the same will happen with Ethereum without Vitalik. Only after that, Ethereum will slowly recover in terms of price and adoption, due to its openness and decentralized nature.
That's the beauty of Ethereum and other cryptocurrencies, which will allow them to survive for future generations. Otherwise, if they were 100% centralized, they'd face certain struggles that will become impossible for them to rise from the ground. Therefore, I believe that Ethereum will become better after Vitalik is out of the picture. Just my opinion