Comment by elevader

The net benefit of using the "separate processes using IPC" model lies in the fact that the language used is an implementation detail that editors/IDEs don't have to care about. Want to write your Rust Language Server in Rust? Fine. Want to write it in Kotlin? Also fine. Your editor is written in JS? Cool. Elisp also works. This wouldn't really work so well if LSPs were some sort of library. IntelliJ plugins are great (if they exist) but they are inherently limited to their own ecosystem, nobody outside of that benefits from that. LSP sure isn't perfect but it is a hell of a lot better than the situation we had before it. If IntelliJ works well for you then that option is always there and hopefully here to stay, all power to you. But not everybody wants that.