(even this association could be done with a local DB similar to mime types if we wanted to simplify)
For example, I don't want a new LSP instance for each file, I want to re-use the same LSP instance if files belong to the same project. For this, my editor needs to understand which directory is the root of the project, and this varies per-language.
In case of neovim, there's a nvim-lspconfig plugin that ships all this configuration and lots of other little nuances. I guess the folks from VSCode preferred lots of little plugins instead of a single big one.
On the other hand, it is kind of unfortunate that this sort of tight integration with language server and editor is happening in the editor which drives/governs the specification itself. I think it would be much more tolerable in regards to the future of the specification if these sorts of "above and beyond" integrations were all happening in any other editor.