What new problem was Nodejs trying to solve and why does it exist?
Well, indeed, Node is a good example of the point I'm making - it provided a full environment for writing programs in JS outside the browser.
There were a plethora of other languages/runtimes available for writing such programs, but Node made this available to people who already knew & liked using JS without having to switch to and/or learn a new language.
Do you have a concrete example to illustate this, and what issues it causes?
On the surface I'm not sure I agree, if what you're saying is people wanting a certain feature should switch languages to get it rather than build it into the language they already use.