Not sure if that is true. Many people are still using vim for many newer languages. I think it depends on the language.
Some languages are simply more IDE-reliant than others. Statically typed languages with a large vocabulary (Java, C#, Scala) tend to benefit more from IDEs than simple, dynamic languages like Python and Ruby.
And there are newer languages like Go. Go was designed to not require an IDE while not being opposed to one.
I think the language server idea is a brilliant one and probably something we'll see more and more of, because it makes a language completely editor/IDE agnostic. It would allow folks using vim or VS code to debug or refactor as cleanly as full-blown IDEs. I suspect this will lead to a decline in the specialized IDE market (Jetbrains).