Just because Ruby and Python are great doesn't mean that they ought to be used for every project. I love being able to write code that compiles to a single statically-linked executable in Rust that pushed me to write more correct code from the start. I also appreciate what Erlang/Elixir offer in terms of fault tolerance, extensive pattern matching and functional programming. There are so many ways to solve problems and that's a good thing. Every one of these languages has tradeoffs, though. People don't move to fancy stacks just for the sake of moving. They're trying to solve old problems by creating new ones!