Lua, especially with LuaJIT, is nearly as fast as C. I certainly don't want to have to run a slow language like Ruby or especially a full blown JS runtime like V8 just to run Vim, the entire point is speed and keyboard ergonomics, otherwise just use VSCode.
You don't need V8 for running JS for scripting, you have quickjs[1] or mquickjs[2] for example. You might have problems importing npm packages, but as we can see from lua plugins you don't even need support for package managers. Performance is not as good as luajit, but it is good enough
