First, you need to ask the question "If Ethereum exists in 10 years" and only then add "- how much will it cost?"
Technologies are changing so quickly that any current leaders, in a couple of years, may become such a backward technology that they will simply disappear from the vastness of the crypto market ...
I doubt Ethereum will disappear a decade from now. It's too big to fail. The project's development team is extremely active, staying ahead of the game whenever possible. While ETH competitors have better features, none have been able to outmatch the original smart contract platform's level of decentralization and censorship-resistance. Besides, the number of dApps on the ETH blockchain are growing at a fast pace. If ETH remains popular, we could experience $5k - $10k per coin ten years from now. The next big upgrade dubbed "ETH 2.0" will make things a lot more interesting to "hodlers".
Nonetheless, a cryptocurrency's future is highly uncertain. The odds of ETH losing ground within the next 10 years are very slim. After all, Ethereum is considered by many as the "Bitcoin of altcoins". It's been nearly 12 years since Bitcoin's inception, yet no other cryptocurrency has been able to take its position on the market. The same thing could happen with Ethereum in the future. What truly matters is usability instead of the price per coin. As long as Ethereum is useful, it won't be going anywhere. Who knows what will happen in a decade? Just my thoughts
Over the course of time, whole empires disappeared, and you mean Ether
In fact, I do not see anything unrealistic in the scenario, if not "leaving the scene" of Ether, then just a strong drop in demand for it. The status of "bitcoin alts" is easy to lose due to more technologically advanced competitors, who also easily and easily support smart contracts from Ethereum. I understand that behind Ether there is a group of large holders who really do not want the "fall of Ethereum", but the technological market also has a process of evolution and the replacement of some "types" with others. Although, I agree that these are just our thoughts, but what is the reality, we will find out after a certain number of years