I agree with you that extending Visual Studio Code is a quite different experience, more akin to pulling teeth or writing COM controls in C++ in the 90s than to extending Emacs, which can be done live in your editing session as you work.
But. Seventy-five percent of developers use Visual Studio Code, with most of the rest being vim, neovim, or JetBrains holdouts. All of the brainpower for extensions and tooling integration is going into Visual Studio Code, not Emacs. Soon, Emacs will simply be left behind.