Scala is very much alive and kicking.
https://redmonk.com/sogrady/2024/09/12/language-rankings-6-2...
The initial hype has died off and that's OK. The hype cycle is inevitable for all languages. Also, predictions rarely happen, mostly because the landscape has changed. Mainstream programming languages can no longer die like Cobol did.
E.g., Java has been dying ever since 2001, surviving the dotcom bubble, .NET, the P in LAMP, Ruby, JS, or Go. Python was supposed to die on its version 3 migration, with people supposedly moving to Ruby.
FWIW, Scala is the world's most popular FP language, it has good tooling, and libraries, and Scala 3 is a wonderful upgrade.
I spent 3 years working on scala tooling in my free time. One of my libraries is used by the vast majority of scala users (it is a dependency of other widely used tools). There was growth from 2018-2023 but it has flatlined over the last year. Right when theoretically it should be getting the boost from scala 3 having now been stable for a bit.
Personally I feel that scala has too much in the language and the compiler is too slow. The tooling is pretty good but it is finicky and ends up getting slow and/or unreliable with larger projects. Even if I were to restrict myself to a small subset of scala, I would still be unsatisfied with the long compile times which was the primary reason I decided to move on.
I don't know if I agree with your contention that languages can't die like COBOL. I think you can relatively easily keep a legacy scala system up, put it in maintenance mode and write new features/products in something else. That is what I expect is already happening with scala and that this trend is likely to accelerate. Keep in mind also that Martin Odersky is nearing retirement age and it's really hard to imagine scala without him. He has much more power/control than the head of most languages.