Ruby eventually failed in term of quantity of developers, means OOP will eventually died. It's not Ruby's fault, it's just the failure of OOP in general.
My prediction, in about 4 years or more, OOP is just an abandon concept for all programmers.
Mind you that (let's say) the modern concept of OOP was invented around second part of 60s (with Simula I think) and I think functional a bit earlier maybe in the beginning of 50s (with LISP I think).
Both paradigms have a lot of years of practice and saying that anyone of them will die in 4 years is I think a bit of exaggeration.
Why do you think that in 4 years OOP will be abandoned by programmers? What is the basis for your assertion?
I think it is more probable that we will have a kind of cross-pollination between these two paradigms with maybe newer languages (or evolving existing languages) to borrow concepts and best practices while still providing the core way to design solutions. This is already happening in smaller scale in multiple languages as far as I see it.
Uh huh. And static typing will replace dynamic for all programmers, functional will replace all uses of imperative, nobody will use whitespace indentation, and all emacs users will switch to vim. Also, every programmer will abandon Windows and macOS for Linux.
Most of the non-system languages on the rise (Kotlin, Swift, Dart, JS, Python, C#) are a mixture of OOP and functional so I don't see OOP dying anytime soon.
My prediction, in about 4 years or more, OOP is just an abandon concept for all programmers.