edit: Just to be clear I don't suggest notepad++ is best at large files. EditPad is clearly the winner in that category. But I do mean to say VSCode and N++ are on par with each other.
Besides, VSCode provides an incredible amount of functionality. So what if it uses as much RAM as my browser. I routinely run multiple browsers, each with multiple windows.
Spotify is a good example of an application that doesn't use Electron (though it uses a similar framework) and still manages to be incredibly slow and bloated. As are most websites. So the problem might not be that Electron is slow... it might just be that the web in general is really slow unless you work extra hard.
And it's still significantly slower than something like Emacs or Sublime (or, dare I say, IntelliJ?). I like, and use, Visual Studio code but it's hardly performant.