> If emacs is so much more extensible, why is there so much better language support for mainstream languages in VSCode?

Writing language support like refactoring and stuff is a huge task, and emacs has a handful of volunteer maintainers, unlike the other tools you mention which have corporate backing behind them with programmers paid to add such support. So emacs could have the same level of support if companies would pay teams for years to develop such features.

But we have language servers now, because it became obvious there is no need to reimplement such support for every editor separately when a server can answer these requests.

Microsoft created LSP for Vscode, but it can be used by any other editor, and emacs too has language server support. I haven't tried it yet, but with LSP it can support the same language features as vscode.

What do you consider "better language support"?

Most emacs users are happy working at the level of "code with some completion", and generally don't want much more.

I write Java in emacs (Ive used netbeans and intellij quite a bit as well) and I cant say I've wanted anything that I dont have.

So... what might I want that you have found to not be available?

I triedVS Code and found it to be not as enjoyable as emacs. Sure, it makes some things easier, but emacs is light years ahead in functionality. I think most of the shortcomings could be addressed with a couple of projects.